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3 years ago

Solve the system of equations by the substitution method.

Mathematics

1 answer:

viva [34]3 years ago

5 0

Answer:

A. (2, -1)

Step-by-step explanation:

(4x - 9) - x = -3

3x - 9 = - 3

3x = 6

x = 2

y = 4(2) - 9

y = 8 -9

y = - 1

(2, -1)

Check

-1 - 2 = -3

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The heights of women aged 20 to 29 are approximately Normal with mean 64 inches and standard deviation 2.7 inches. Men the same

masha68 [24]

Answer: The z-scores for a woman 6 feet tall is 2.96 and the z-scores for a a man 5'10" tall is 0.25.

Step-by-step explanation:

Let x and y area the random variable that represents the heights of women and men.

Given : The heights of women aged 20 to 29 are approximately Normal with mean 64 inches and standard deviation 2.7 inches.

i.e. $\mu_1 = 64$ $\sigma_1=2.7$

Since , $z=\dfrac{x-\mu}{\sigma}$

Then, z-score corresponds to a woman 6 feet tall (i.e. x=72 inches).

[∵ 1 foot = 12 inches , 6 feet = 6(12)=72 inches]

$z=\dfrac{72-64}{2.7}=2.96296296\approx2.96$

Men the same age have mean height 69.3 inches with standard deviation 2.8 inches.

i.e. $\mu_2 = 69.3$ $\sigma_2=2.8$

Then, z-score corresponds to a man 5'10" tall (i.e. y =70 inches).

[∵ 1 foot = 12 inches , 5 feet 10 inches= 5(12)+10=70 inches]

$z=\dfrac{70-69.3}{2.8}=0.25$

∴ The z-scores for a woman 6 feet tall is 2.96 and the z-scores for a a man 5'10" tall is 0.25.

6 0

3 years ago

Nicholas wrote the steps below to simplify the fraction 20/30. Find his error and correct it. 20/30= 20÷5=4 30÷6=5

aksik [14]

Answer:2/3

Step-by-step explanation:

7 0

3 years ago

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What is the area of this polygon?

Dennis_Churaev [7]

Answer:

34.5 units

Step-by-step explanation:

Divide the composite figure into different shapes and then find the areas of all the shapes and add them together to find the total area. We could divide this into 3 triangles and 1 rectangle.

4 0

3 years ago

What is the answer to 11 > b + 4 > -6

Anestetic [448]

$11 > b+4 > -6\\11 - 4 > b > -6-4\\7 > b > -10$

Hope that helps!

7 0

2 years ago

Use the quadratic formula to find the solutions to the equation.<br> 3x2 - 10x + 5 = 0

Nitella [24]

Answer: A

Step-by-step explanation:

3x² - 10x + 5 = 0

a = 3 b = -10 c = 5

Δ = b²- 4ac = 100 - 4.3.5 = 40 > 0 => have 2 solutions

=> x = $\frac{10+\sqrt{40} }{6}$ or x = $\frac{10-\sqrt{40} }{6}$

3 0

3 years ago

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