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3 years ago

Which of the following expressions is equivalent to a(4-a)-5(a+7)

Mathematics

2 answers:

MissTica3 years ago

5 0

Answer:

-a² - a - 35

Step-by-step explanation:

a(4 - a) - 5(a + 7)

(4a - a²) - (5a + 35)

4a - a² - 5a - 35

-a² - a - 35

Licemer1 [7]3 years ago

4 0

Answer:

dude give answer choices

Step-by-step explanation:

You might be interested in

If Jay ran 1 mile in 10 minutes on Monday, 2 miles in 20 minutes on Tuesday,

earnstyle [38]

Answer:

4 miles

Step-by-step explanation:

5 0

3 years ago

In the past, 21% of all homes with a stay-at-home parent, the father is the stay-at-home parent. An independent research firm ha

Afina-wow [57]

Answer:

A sample size of 79 is needed.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$\pi = 0.21$

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.09?

A sample size of n is needed.

n is found when M = 0.09. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.09 = 1.96\sqrt{\frac{0.21*0.79}{n}}$

$0.09\sqrt{n} = 1.96\sqrt{0.21*0.79}$

$\sqrt{n} = \frac{1.96\sqrt{0.21*0.79}}{0.09}$

$(\sqrt{n})^{2} = (\frac{1.96\sqrt{0.21*0.79}}{0.09})^{2}$

$n = 78.68$

Rounding up to the nearest whole number.

A sample size of 79 is needed.

4 0

3 years ago

In a certain chemical, the ratio of zinc to copper is 3 to 17. A jar of the chemical contains 799 grams of copper. How many gra

dezoksy [38]

Answer:

let's see what to do buddy...

Step-by-step explanation:

$\frac{zinc}{copper} = \frac{3}{17} \\ \\ \frac{zinc}{799} = \frac{3}{17}$

Multiply the sides of the equation by 799

$zinc = \frac{3}{17} \times 799 \\ \\ zinc = \frac{3}{17} \times 17 \times 47 \\ \\ zinc = 3 \times 47 = 141$

So A jar of the chemical contains 141 grams of zinc.

And we're done.

Thanks for watching buddy good luck.

♥️♥️♥️♥️♥️

8 0

3 years ago

Choose the correct answer: 15 is 3% of (A) 1.5 (B) 2.5 (C) 500 (D) 5000

eduard

Answer:

c) 500

Step-by-step explanation:

3% = 0.03

multiply the decimal from of 3% by 500:

500 x 0.03

solve:

500 x 0.03 = 15

3 0

2 years ago

Drag a reason to each box to complete this proof. If 12=13x+5 , then x = 21.

Ainat [17]

I think the answers are:

Statement Reason
12=13x+5 Given
7=13x Subtraction Property of Equality
21 = x Multiplication Property of Equality
x = 21 Symmetric Property of Equality

By the way, I'm doing the same exam for Geometry as well. There's a lot of proof questions on there which I'm not good at doing for the reasoning part. If you finish the exam before I do, maybe you can message me what the answers are for some of the questions on there so I know if my answers for the questions are incorrect or not.

Besides that, hope the answer above is correct for you.

~ ShadowXReaper069

5 0

2 years ago

Read 2 more answers