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3 years ago

Simplified 2(x + 8) + 3(x -9)

Mathematics

1 answer:

slava [35]3 years ago

5 0

Answer:

5x - 11

Step-by-step explanation:

Step 1: Write out expression

2(x + 8) + 3(x - 9)

Step 2: Distribute

2x + 16 + 3x - 27

Step 3: Combine like terms (x)

5x + 16 - 27

Step 4: Combine like terms (constants)

5x - 11

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The mayor is interested in finding a 98% confidence interval for the mean number of pounds of trash per person per week that is

saul85 [17]

Solution :

Given :

Sample mean, $\overline X = 34.2$

Sample size, n = 129

Sample standard deviation, s = 8.2

a. Since the population standard deviation is unknown, therefore, we use the t-distribution.

b. Now for 95% confidence level,

α = 0.05, α/2 = 0.025

From the t tables, T.INV.2T(α, degree of freedom), we find the t value as

t =T.INV.2T(0.05, 128) = 2.34

Taking the positive value of t, we get

Confidence interval is ,

$\overline X \pm t \times \frac{s}{\sqrt n}$

$34.2 \pm 2.34 \times \frac{8.2}{\sqrt {129}}$

(32.52, 35.8)

95% confidence interval is (32.52, 35.8)

So with $95 \%$ confidence of the population of the mean number of the pounds per person per week is between 32.52 pounds and 35.8 pounds.

c. About $95 \%$ of confidence intervals which contains the true population of mean number of the pounds of the trash that is generated per person per week and about $5 \%$ that doe not contain the true population of mean number of the pounds of trashes generated by per person per week.

4 0

3 years ago

The class treasury contained 30$ in nickels and dimes. If there were 500 coins than how many coins of each type are there?

Alenkasestr [34]

Equation 1. N+D=500

equation 2 5N+10D=3000
This is for equation 1
N=500-d
Substitute into equations 2 and solve for D
5N+10D=3000
5(500-D)+10D=3000
2500-5D+10D=3000
5D=500
D=100
Lets go back the equation 1
N=500-D
N=500-100
N=400
there are 400 Nickles and 100 Dimes

7 0

3 years ago

If your scale factor is 3/4, how will the scaled copy compare to the original?

Kisachek [45]

A scaled copy with the scale factor being 3/4 it would be smaller because it’s less than one so whenever there is a fraction that’s less than one then the shape would be smaller aswell

3 0

3 years ago

NEED HELP FAST!!

Dafna11 [192]

Answer:

see below

Step-by-step explanation:

dilation with a scale factor of 1/3 means the distances to the center shrink by 1/3

so for center (4,-2)

distance of (7,4) is 3 n 6 to center

1/3 of distance = 1 n 2

so (7,4) become (4+1, -2+2) = (5, 0) after the dilation

similarly u can find the other 2 pts

distance of (-2,4) is -6 n 6 to center

1/3 of distance = -2 n 2

so (-2,4) become (4-2, -2+2) = (2, 0) after the dilation

distance of (1, 10) is -3 n 12 to center

1/3 of distance = -1 n 4

so (1,10) become (4-1, -2+4) = (3, 2) after the dilation

plot the new triangle using the 3 pts

8 0

3 years ago

Consider the following problem: A farmer with 750 ft of fencing wants to enclose a rectangular area and then divide it into four

gregori [183]

Answer and step-by-step explanation:

For any rectangle, the one with the largest area will be the one whose dimensions are as close to a square as possible.

However, the dividers change the process to find this maximum somewhat.

Letting x represent two sides of the rectangle and the 3 parallel dividers, we have 2x+3x = 5x.

Letting y represent the other two sides of the rectangle, we have 2y.

We know that 2y + 5x = 750.

Solving for y, we first subtract 5x from each side:

2y + 5x - 5x = 750 - 5x

2y = -5x + 750

Next we divide both sides by 2:

2y/2 = -5x/2 + 750/2

y = -2.5x + 375

We know that the area of a rectangle is given by

A = lw, where l is the length and w is the width. In this rectangle, one dimension is x and the other is y, making the area

A = xy

Substituting the expression for y we just found above, we have

A = x(-2.5x+375)

A = -2.5x² + 375x

This is a quadratic equation, with values a = -2.5, b = 375 and c = 0.

To find the maximum, we will find the vertex. First we find the axis of symmetry, using the equation

x = -b/2a

x = -375/2(-2.5) = -375/-5 = 75

Substituting this back in place of every x in our area equation, we have

A = -2.5x² + 375x

A = -2.5(75)² + 375(75) = -2.5(5625) + 28125 = -14062.5 + 28125 = 14062.5

6 0

3 years ago