Use the distributive property to rewrite each algebraic expression: Do not solve, just rewrite.

1 answer:

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Use the distributive property to rewrite each algebraic expression: Do not solve, just rewrite.

1) 8(x + 7) = 8x + 56

2) 5(x - 10) = 5x - 50

3) 6(11 + x) = 66 + 6x

Factor each expression. (Pull a common factor from each number)

COMPLETED EXAMPLE: 27 + 12 = 3(9 + 4) → (3 is the shared factor for 27 and 12)

4) 12 + 36 = 12 (1 + 3)

5) 16 + 20 = 4 (4 + 5)

Solve each expression using the distributive property.

6) 4 x 82 = 4 (80 + 2) = 320 + 8 = 328

7) 12 x 44 = 12 (40 + 4) = 480 + 48 = 528

8) Mrs. S bought 9 folders and 9 notebooks. The cost of each folder was $2.50. Each notebook cost $4. First, write an expression for the problem then find the total cost.

Expression = 9f + 9n = 9($2.50) + 9($4)

Total cost =9($2.50) + 9($4) = $22.5 + $36 = $58.5

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A phone manufacturer wants to compete in the touch screen phone market. He understands that the lead product has a battery life

alisha [4.7K]

Answer:

The null hypothesis is $H_0: \mu \leq 10$

The alternative hypothesis is $H_1: \mu > 10$

b-1) The value of the test statistic is t = 1.86.

b-2) The p-value is of 0.0348.

Step-by-step explanation:

Question a:

Test if the battery life is more than twice of 5 hours:

Twice of 5 hours = 5*2 = 10 hours.

At the null hypothesis, we test if the battery life is of 10 hours or less, than is:

$H_0: \mu \leq 10$

At the alternative hypothesis, we test if the battery life is of more than 10 hours, that is:

$H_1: \mu > 10$

b-1. Calculate the value of the test statistic.

The test statistic is:

We have the standard deviation for the sample, so the t-distribution is used to solve this question

$t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, s is the standard deviation and n is the size of the sample.

10 is tested at the null hypothesis:

This means that $\mu = 10$

In order to test the claim, a researcher samples 45 units of the new phone and finds that the sample battery life averages 10.5 hours with a sample standard deviation of 1.8 hours.

This means that $n = 45, X = 10.5, s = 1.8$