Quadratic Formula: (-b +/- sqrt(b^2 - 4ac)) / 2a
2x^2 - 3x = 12
2x^2 - 3x - 12 = 0
a = 2
b = -3
c = -12
(--3 +/- sqrt( (-3)^2 - 4(2)(-12) )) / 2(2)
3 +/- sqrt( 9 + 96 ) / 4
3 +/- sqrt(105) / 4
Answers: [tex]\frac{3 + \sqrt{105} }{4}[/tex], [tex]\frac{3 - \sqrt{105} }{4}[/tex]
Hope this helps!
what number increased by 130% is 69
Answer:
The number is 30.
Step-by-step explanation:
Let the number be x
so
x + (130% of x) = 69
x + 13x/10 = 69
or, (10x + 13x)/10 = 69
or, 23x = 690
or, x = 690/23
so, x = 30
Answer: 30
Step-by-step explanation:
its correct on rsm
A company that produces DVD drives has a 12% defective rate. Let X represent the number of defectives in a random sample of 55 of their drives.
Required:
a. What is the probability the sample will contain exactly 8 defective drives?
b. What is the probability the sample will contain more than 8 defective drives?
c. What is the probability the sample will contain less than 8 defective drives?
d. What is the expected number of defective drives in the sample?
Answer:
a) 0.1287 = 12.87% probability the sample will contain exactly 8 defective drives
b) 0.2092 = 20.92% probability the sample will contain more than 8 defective drives.
c) 0.6621 = 66.21% probability the sample will contain less than 8 defective drives.
d) The expected number of defective drives in the sample is 6.6
Step-by-step explanation:
For each DVD, there are only two possible outcomes. Either it is defective, or it is not. The probability of a DVD being defective is independent of any other DVD, which means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
A company that produces DVD drives has a 12% defective rate.
This means that [tex]p = 0.12[/tex]
Let X represent the number of defectives in a random sample of 55 of their drives.
This means that [tex]n = 55[/tex]
a. What is the probability the sample will contain exactly 8 defective drives?
This is [tex]P(X = 8)[/tex]. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 8) = C_{55,8}.(0.12)^{8}.(0.88)^{47} = 0.1287[/tex]
0.1287 = 12.87% probability the sample will contain exactly 8 defective drives.
b. What is the probability the sample will contain more than 8 defective drives?
This is:
[tex]P(X > 8) = 1 - P(X \leq 8)[/tex]
In which:
[tex]P(X \leq 8) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8)[/tex]
Then
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{55,0}.(0.12)^{0}.(0.88)^{55} = 0.0009[/tex]
[tex]P(X = 1) = C_{55,1}.(0.12)^{1}.(0.88)^{54} = 0.0066[/tex]
[tex]P(X = 2) = C_{55,2}.(0.12)^{2}.(0.88)^{53} = 0.0244[/tex]
[tex]P(X = 3) = C_{55,3}.(0.12)^{3}.(0.88)^{52} = 0.0588[/tex]
[tex]P(X = 4) = C_{55,4}.(0.12)^{4}.(0.88)^{51} = 0.1043[/tex]
[tex]P(X = 5) = C_{55,5}.(0.12)^{5}.(0.88)^{50} = 0.1450[/tex]
[tex]P(X = 6) = C_{55,8}.(0.12)^{6}.(0.88)^{49} = 0.1648[/tex]
[tex]P(X = 7) = C_{55,7}.(0.12)^{7}.(0.88)^{48} = 0.1573[/tex]
[tex]P(X = 8) = C_{55,8}.(0.12)^{8}.(0.88)^{47} = 0.1287[/tex]
So
[tex]P(X \leq 8) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) = 0.0009 + 0.0066 + 0.0244 + 0.0588 + 0.1043 + 0.1450 + 0.1648 + 0.1573 + 0.1287 = 0.7908[/tex]
[tex]P(X > 8) = 1 - P(X \leq 8) = 1 - 0.7908 = 0.2092[/tex]
0.2092 = 20.92% probability the sample will contain more than 8 defective drives.
c. What is the probability the sample will contain less than 8 defective drives?
This is:
[tex]P(X < 8) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7)[/tex]
With the values we found in b.
[tex]P(X < 8) = 0.0009 + 0.0066 + 0.0244 + 0.0588 + 0.1043 + 0.1450 + 0.1648 + 0.1573 = 0.6621[/tex]
0.6621 = 66.21% probability the sample will contain less than 8 defective drives.
d. What is the expected number of defective drives in the sample?
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
In this question:
[tex]E(X) = 55(0.12) = 6.6[/tex]
The expected number of defective drives in the sample is 6.6
if the Arithmetic means of the 17 numbers is 14. when the two numbers are eliminated the mean becomes 13 if the differences of the two eliminated numbers is 7. find the numbers.
Answer=30,20 but show me in process.
Answer:
The numbers are 18 and 25
Step-by-step explanation:
Given
[tex]\bar x_1 = 14[/tex] [tex]n_1 = 17[/tex]
[tex]\bar x_2 = 13[/tex] [tex]n_2 = 15[/tex]
[tex]a - b = 7[/tex] --- the difference of the 2 numbers
Required
Find a and b
We have:
[tex]\bar x = \frac{\sum x}{n}[/tex] -- mean formula
So, we have:
[tex]\bar x_1 = \frac{\sum x_1}{n_1}[/tex]
[tex]14 = \frac{\sum x_1}{17}[/tex]
Cross multiply
[tex]\sum x_1 = 14 * 17[/tex]
[tex]\sum x_1 = 238[/tex]
When the two numbers are removed, we have:
[tex]\bar x_2 = \frac{\sum x_2}{n_2}[/tex]
[tex]13 = \frac{\sum x_2}{15}[/tex]
Cross multiply
[tex]\sum x_2 = 13 * 15[/tex]
[tex]\sum x_2 = 195[/tex]
The two numbers that were removed are:
[tex]a + b = \sum x_1 - \sum x_2[/tex]
[tex]a + b = 238 - 195[/tex]
[tex]a + b = 43[/tex]
Make a the subject
[tex]a= 43 - b[/tex]
We have:
[tex]a - b = 7[/tex]
Substitute [tex]a= 43 - b[/tex]
[tex]43 - b - b = 7[/tex]
[tex]43 - 2b = 7[/tex]
Collect like terms
[tex]2b = 43 - 7[/tex]
[tex]2b = 36[/tex]
Divide by 2
[tex]b = 18[/tex]
Substitute [tex]b = 18[/tex] in [tex]a= 43 - b[/tex]
[tex]a = 43 - 18[/tex]
[tex]a = 25[/tex]
Determine which type of error is most likely to arise from the following situations. a 1. the time in which individuals are contacted to take a survey occurs during work hours f 2. the last part of a newspaper article asks readers to mail or email the newspaper their opinion about universal health coverage 3. subjects are asked to recall how often they snacked between meals in the past 30 days 4. a survey to assess teachers' opinions about Common Core uses a member list for the largest teachers' union as the sampling frame a. question wording b. undercoverage c. processing error d. bad sampling method e. response error f. nonresponse g. random sampling error
Answer:
Determination of type of error arising from the situations
Situation Type of Error
1. Nonresponse
2. Bad sampling method
3. Question wording
4. Undercoverage
Step-by-step explanation:
Types of errors:
a. question wording means that the manner a question is worded elicits some particular responses, which may not accurately reflect reality.
b. undercoverage occurs when some elements of the target population is not represented on the survey frame.
c. processing error arises from data processing
d. bad sampling method is caused by the voluntariness of those who choose to respond.
e. response error is caused by a questionnaire that requires framing improvements, misinterpretation of questions by interviewers or respondents, and errors in respondents' statements.
f. nonresponse error arises as a result of incomplete information or partial response.
g. random sampling error arises from the limited sample size when compared with the population size.
= 10 + 3
=13
Example 6
If f(x) = 2x + 1, g(x) = 3x - 2 and fg(x) = 5, find the value of x,
Answer:
f(x) = 2x + 1, g(x) = 3x - 2 and fg(x) = 5
Step-by-step explanation:
Question 26 of 58
Mr. Nguyen recorded the numbers of students in his homeroom class who
participated in spirit week.
The table shows the number of students who dressed up each day.
Day
Mon Tues. Wed. Thurs. Fri. Total
Number of students 2
2
5
5
6
20
Find the mean and the median of the data set.
Determine which of these values is greater.
O A. The mean, 5, is greater than the median, 4.
OB. The mean, 5, is greater than the median, 2.
O c. The median, 6, is greater than the mean, 2.
O D. The median, 5, is greater than the mean, 4.
Answer:
D
Step-by-step explanation:
The answer is D.
An education researcher would like to test whether 2nd graders retain or lose knowledge during the summer when they are presumably not in school. She asks nine 2nd graders to take a comprehension exam at the end of the school year (May), and then asks those same students to come back after the summer (late August) to retake a different but equivalent exam, to see if their level of comprehension has changed. Using the data below, test this hypothesis using an (alpha level of 0.05.)
May August
95 100
72 80
78 95
50 65
89 85
92 98
75 70
90 96
65 87
Required:
What is the appropirate test?
Answer:
Kindly check explanation
Step-by-step explanation:
Given the data:
May August
95 100
72 80
78 95
50 65
89 85
92 98
75 70
90 96
65 87
The appropriate test is a paired t test :
d = difference between May and August
d = (-5, -8, -17, -15, 4, -6, 5, -6, -22)
The hypothesis :
H0 : μd = 0
H1 : μd ≠ 0
The test statistic :
T = dbar / (Sdbar/√n)
Where, dbar and Sdbar are the mean and standard deviation of 'd' respectively.
Using calculator :
dbar = - 7.777 ; Sdbar = 9.052
Test statistic = - 7.777 / (9.052 /√9)
Test statistic = - 2.577
The Pvalue, df = n - 1 = 9 - 1 = 8
Pvalue(-2.577, 8) = 0.0327
At α = 0.05
Pvalue < α ; WE reject the H0 ; and conclude that there has been a change in score
NEED HELP ASAPPPPP !!!
Answer:
2160
Step-by-step explanation:
because c is 15 and d is 12 therefore d² is 144 and 144x15 is 2160
Answer:
2160
Step-by-step explanation:
Substitute
[tex](15)(12) {}^{2} [/tex]
[tex]15 \times 144 = 2160[/tex]
(SAT PREP) Find the value of x in each of the following excersises
Answer:
The answer is 155.
Step-by-step explanation:
We can find the remaining parts of the triangle angles.
Which describes the correlation shown in the scatterplot?
On a graph, points are grouped closely together and increase.
There is a positive correlation in the data set.
There is a negative correlation in the data set.
There is no correlation in the data set.
More points are needed to determine the correlation.
Answer:
More points are needed to determine the correlation.
Answer:
its d
Step-by-step explanation:
;)
The point (7, 8) is the solution of which of the following systems of equations?
1. 8x - y = 48
9x + 10y = 142
2. 9x - y = 55
8x + 10y = 140
3. x-6y=-41
8x + 9y = 127
4. x-7y=-49
10x + 9y = 142
Option 4
Verification:-
[tex]\\ \sf\longmapsto x-7y=-49[/tex]
[tex]\\ \sf\longmapsto 7-7(8)=-49[/tex]
[tex]\\ \sf\longmapsto 7-56=-49[/tex]
[tex]\\ \sf\longmapsto -49=-49[/tex]
And
[tex]\\ \sf\longmapsto 10x+9y=142[/tex]
[tex]\\ \sf\longmapsto 10(7)+9(8)=142[/tex]
[tex]\\ \sf\longmapsto 70+72=142[/tex]
[tex]\\ \sf\longmapsto 142+142[/tex]
Hence verified
Answer:
4.
Step-by-step explanation:
1. 8x - y = 48
9x + 10y = 142
8(7) - 8 = 48
9(7) + 10(8) = 143
No
2. 9x - y = 55
8x + 10y = 140
9(7) - 8 = 55
9(7) - 10(7) = -24
No
3. x-6y=-41
8x + 9y = 127
7 - 6(8) = -41
8(7) + 9(8) = 128
No
4. x-7y=-49
10x + 9y = 142
7 - 7(8) = 49
10(7) + 9(8) = 142
Yes
Solve the system of equations.
4x + 3y + 5z = 6
6x + 8y + 6z = 4
4x + 2y + z = 8
(x = 1, y = -1,2 = 1)
b. (x = 3, y = -3,2 = 3)
a.
C. (x = 0, y = 0, 2 = 2)
d. (x - 2, y --2, z = 0)
A height of 2.5 cm represents 100 goats. What should be the height for 170 goats?
Answer: 4.25
Step-by-step explanation:
2.5/100 = 0.025
0.025 × 170 = 4.25
but the question there is any goats in 2.5 cm ??
that is impossible
Write a quadratic function f whose zeros are 4 and 1
9514 1404 393
Answer:
f(x) = (x -4)(x -1)
Step-by-step explanation:
If 'a' is a zero of the function, then (x -a) is a factor. The two zeros mean the factored form of the quadratic is ...
f(x) = (x -4)(x -1)
__
The expanded form will be ...
f(x) = x² -5x +4
What is the lengh of the line
Answer:
√45 or 3√5
Step-by-step explanation:
perimeter of a circle 8 centimeter wide
Answer:
25.13 cm
Step-by-step explanation:
Perimeter ( circumference ) of a circle = 2πr
Given,
The circle is 8 cm wide
which means,
The diameter (d) of the circle is 8 cm.
Radius (r) of the circle = d/2
= 8/2
= 4
Radius = 4 cm
Putting the value in the formula;
2πr
= 2 (22/7) (4)
= 25.13 cm (approx)
Algebra two divide plz help
Answer:
- x³ - 2x² + 3 - 1 / x
Step-by-step explanation:
(4x³ - 8x² + 12x - 4) / (-4x)
- x³ - 2x² + 3 - 1 / x
Find the most general antiderivative of the function. (Check your answer by differentiation. Use C for the constant of the antiderivative. Remember to use absolute values where appropriate.)
f(x) = 45−5x, x>0 .
Answer:
F(x) = 45*x - (5/2)*x^2 + C
Step-by-step explanation:
Here we want to find the antiderivative of the function:
f(x) = 45 - 5*x
Remember the general rule that, for a given function:
g(x) = a*x^n
the antiderivative is:
G(x) = (a/(n + 1))*a*x^(n + 1) + C
where C is a constant.
Then for the case of f(x) we have:
F(x) = (45/1)*x^1 - (5/2)*x^2 + C
F(x) = 45*x - (5/2)*x^2 + C
Now if we derivate this, we get:
dF(x)/dx = 1*45*x^0 - 2*(5/2)*x
dF(x)/dx = 45 - 5*x
4. (08.02 MC)
Factor completely 2x3 + 10x2 + 14x + 70. (5 points)
(2x^2 + 14)(x + 5)
(x^2 + 7)(2x + 10)
2(x^3 + 5x2 + 7x + 35)
2[(x^2 + 7)(x + 5)]
Answer:
2[(x^2 + 7)(x + 5)]
Step-by-step explanation:
Note that the ratio of the first and second terms is the same as that between the third and fourth terms. So this cubic will factor by grouping, but first we can separate out the common scalar factor 2...
2x3+10x2+14x+70=
2(x3+5x2+7x+35)
2((x3+5x2)+(7x+35))
2(x2(x+5)+7(x+5))
2(x2+7)(x+5)
Answer:
The answer is D. 2[(x2 + 7)(x + 5)]
Step-by-step explanation:
find the missing length indicated
Answer:
192
Step-by-step explanation:
geometric mean theorem :
with p and q being the segments of the Hypotenuse, then
h = x = sqrt(p×q)
p = 144
q = 400-144 = 256
h = x = sqrt(144×256) = 12×16 = 192
What is the value of x?
2
3
6
7
Answer:
i think 3
Step-by-step explanation:
Answer: [A] 2
Step-by-step explanation:
100% on edge 2023
Identify the pair numbers
Answer:
D. 212 degrees Fahrenheit and 100 degrees Celsius.
Step-by-step explanation:
The boiling point of water in Celsius is 100.
The way to calculate Celsius to Fahrenheit:
F = (C × 9/5) + 32
So we plug in 100 for C.
F = (100 × 9/5) + 32
F = 180 + 32
F = 212
Therefore, the numbered pair is 212 degrees F and 100 degrees C.
Please helps fill in the charts
A and b
With order of pairs
Answer:
...
Step-by-step explanation:
seeee the above picture
Two solutions of the equation Ax+By = 1 are (2, -1) and (-3,-2). Find A and B.
Answer:
Substitute in the values of both given coordinates & form 2 equations:
[tex]\left \{ {{A(2)+B(-1)=1} \atop {A(-3)+B(-2)=1}} \right. \\\\=\left \{ {{2A-B=1} \atop {-3A-2B=1}} \right.[/tex]
Find the value of B from the equation 2A - B = 1:
[tex]2A-B=1\\-B=1-2A\\B=2A-1[/tex]
Substitute in the B-value to the other equation:
[tex]-3A-2B=1\\-3A-2(2A-1)=1\\-3A-4A+2=1\\-7A=1-2\\-7A=-1\\A=\frac{-1}{-7} =\frac{1}{7}[/tex]
Find the B-value using the equation from before:
[tex]B=2A-1=2(\frac{1}{7})-1=\frac{2}{7} -\frac{7}{7} =-\frac{5}{7}[/tex]
Therefore the equation Ax + By = 1 would equal:
[tex]\frac{1}{7} x-\frac{5}{7} y=1[/tex]
Select the correct answer.
What is the value of this expression when x = -6 and ?
4(x2 + 3) − 2y
Answer:
D. 157
Step-by-step explanation:
4(x^2+3)-2y
4(6^2+3)-2(-1/2) add in given values
4(39)+1. start with parentheses
156+1. combine like terms
157. answer
Answer:
D. 157
Step-by-step explanation:
Hi there!
We want to find the value of the expression 4(x²+3)-2y is when x=-6 and y=-1/2
Let's first simplify the expression, as that will likely make it easier
Distribute 4 to both x² and 3
4x²+12-2y
That's the expression
Substitute -6 as x into the expression
4(-6)²+12-2y
Raise (-6) to the second power
4*36+12-2y
Multiply 36 by 4
144+12-2y
Add 12 and 144 together
156-2y
Now the expression is 156-2y
But remember that we know that y=-1/2, and we haven't substituted it into the expression yet
Substitute -1/2 as y into the expression
156-2(-1/2)
Multiply
156+2/2
Simplify
156+1
Add
157
Hope this helps!
Mr. Allway’s math class surveyed all the seventh-grade students to find out their favorite sport. The following circle graph shows a breakdown of the survey findings.
Find the number of degrees represented by Basketball.
108°
101°
11°
140°
Answer:
101 is the answer of the question
Answer:
101 degrees
Step-by-step explanation:
First you add all the percentages
39 + 28 + 30 + 3 = 100%
To find the number of degrees of basketball you multiply 28% by 360 because it’s a circle.
28/100 * 360 = 10,080/100 = 100.8 ~ 101
find an odd natural numbers x such that LCM (x, 40) = 1400
Answer:
175
Step-by-step explanation:
so, the LCM is the combination of the longest chains of the prime factors in every number.
40 : 2, 2, 2, 5
1400 / 40 = 35
35 : 5, 7
but LCM(35, 40) = 2×2×2×5×7 = 280
and not 1400.
what is missing ?
1400 / 280 = 5
aha, another prime factor 5 is missing to get 1400.
x : 5, 5, 7
so, x = 5×5×7 = 175
LCM(175, 40) = 2×2×2×5×5×7 = 1400
A concert promoter sells tickets and has a marginal-profit function given below, where P'(x) is in dollars per ticket. This means that the rate of
change of total profit with respect to the number of tickets sold, x, is P'(x). Find the total profit from the sale of the first 380 tickets, disregarding any
fixed costs.
P'(x) = 2x - 1198
The total profit is $
Answer:
The answer is "-310840".
Step-by-step explanation:
[tex]\begin{array}{l} P'(x) = 2x - 1198\\ \\ \frac{{dP}}{{dx}} = 2x - 1198\\ \\ dP = \left( {2x - 1198} \right)dx\\ \\ \int {dP} = \int\limits_0^{380} {\left( {2x - 1198} \right)dx} \\ \\ P = \left( {2\frac{{{x^2}}}{2} - 1198x} \right)_0^{380}\\ \\ P = {380^2} - 1198 \times 380 = 144400-455240=-310840\\ \end{array}[/tex]
I'm stuck. Can anyone help please?
log₉(x - 7) + log₉(x - 7) = 1
2 log₉(x - 7) = 1
log₉(x - 7) = 1/2
Take the base-9 antilogarithm of both sides; in other words, make both sides powers of 9:
[tex]9^{\log_9(x-7)} = 9^{1/2}[/tex]
[tex]9^{1/2}[/tex] can also be written as √9 = 3, and [tex]b^{\log_b(a)}=a[/tex], so the equation reduces to
x - 7 = 3
Solve for x :
x = 10
which graph correctly represents this 2y+x=-5and y+3x=0
Answer:
you didn't feature any graphs for me to choose from
