All categories

3 years ago

1.Write this sentence as an equation.Do not solve it.

Mathematics

1 answer:

Ivahew [28]3 years ago

7 0

Problem 1

x = some unknown number

3x = three times a number

3x-7 = difference of three times a number and seven

2(3x-7) = two times the difference of three times a number and seven

2(3x-7) = x

The last equation is formed because the expression we built up is equal to the original number in question

<h3>Answer: 2(3x-7) = x</h3>

===========================================================

Problem 2

Use the distribution rule to get

3(2x+4)-2x

3*2x+3*4-2x

6x+12-2x

From here, we combine like terms. That means we combine the 6x and -2x to get 4x

So 6x+12-2x simplifies to 4x+12 and not 16x

How did she get 16x? Possibly because she mistakenly thought she could add 4x to 12 to get 16x. This only works if the 12 had x attached to it.

In other words, this is valid: 4x+12x = 16x but this is not 4x+12 = 16x

===========================================================

Problem 3

L = length = horizontal dimension = (d+15) ft

W = width = vertical dimension = (d-3) ft

P = perimeter of the rectangle = 108 ft

P = 2(L+W)

108 = 2(d+15+d-3)

108 = 2(2d+12)

108 = 4d+24

4d+24 = 108

4d = 108-24

4d = 84

d = 84/4

d = 21

The deep end is 21 feet long.

This means the overall horizontal length is d+15 = 21+15 = 36 feet and the the vertical width is d-3 = 21-3 = 18 feet

The overall dimensions of the rectangular pool are 36 ft by 18 ft

<h3>Answer: d = 21</h3>

You might be interested in

Help me! I'll give brainliest.

blsea [12.9K]

Answer:

T = 48

Step-by-step explanation:

The equation would be 96-(8 x 6) = 48

4 0

2 years ago

Read 2 more answers

Mark, Carlos, Ben, and Taj ran the 1,600-meter relay today at the track meet. If their times were 55.2 seconds, 54.34 seconds, 5

ad-work [718]

55.2+54.34+55.16+52.08 = 216.77
So A

4 0

2 years ago

Read 2 more answers

Number 14 please help

liberstina [14]

I think you should say you multipliyed?

4 0

3 years ago

Read 2 more answers

Write a short paragraph composes at least 10 sentences<br>discussing factors affecting solubility

kumpel [21]

Answer:

Step-by-step explanation:

Solubility can be defined as the ability of a solute (could be solid, liquid or gas) to dissolve in a solvent in order to produce a solution. There are several factors affecting solubility which includes (basically four) temperature, polarity, surface area of solute particles and pressure of gases. Generally, an increase in temperature leads to an increase in the solubility of a solute in a solvent. This is because an increase in temperature will increase the average kinetic energy of molecules in the solution which leads to increase interaction between the solute and solvent particles. There is a general saying of "like dissolve like" when discussing polarity. For example, organic solvents are used to dissolve organic solutes (just as petrol is used to wash grease off hands and surfaces). Hence, when the solute and solvent have the same polarity, solubility occurs easily, otherwise solubility may be difficult or may not even occur. A reduced/smaller surface area of the solute leads to an increase in solubility as this makes it easy for the solute particles to interact easily with the solvent. In gases, an increase in pressure increases the interaction between the gaseous molecules of the solute and the solvent, thus leading to an increased solubility. Pressure does not affect solubility in solids and rarely in liquids.

3 0

3 years ago

A laptop producing company also produces laptop batteries, and claims that the batteries

gregori [183]

Answer:

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours. (P-value = 0).

The null and alternative hypothesis are:

$H_0: \mu=4\\\\H_a:\mu< 4$

Step-by-step explanation:

<em>The question is incomplete: To test this claim a sample or population standard deviation is needed.</em>

<em>We will estimate that the sample standard deviation is 2 hours, and use a t-test to test that claim.</em>

<em> NOTE (after solving): The difference between the sample mean and the mean of the null hypothesis is big enough to reject the null hypothesis, even when we have a sample standard deviation of 3.5 hours, which can be considered bigger than the maximum standard deviation for the sample.</em>

This is a hypothesis test for the population mean.

The claim is that the batteries power the laptops for significantly less than 4 hours.

Then, the null and alternative hypothesis are:

$H_0: \mu=4\\\\H_a:\mu< 4$

The significance level is 0.05.

The sample has a size n=500.

The sample mean is M=3.5.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=2.

The estimated standard error of the mean is computed using the formula:

$s_M=\dfrac{s}{\sqrt{n}}=\dfrac{2}{\sqrt{500}}=0.0894$

Then, we can calculate the t-statistic as:

$t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{3.5-4}{0.0894}=\dfrac{-0.5}{0.0894}=-5.5902$

The degrees of freedom for this sample size are:

$df=n-1=500-1=499$

This test is a left-tailed test, with 499 degrees of freedom and t=-5.5902, so the P-value for this test is calculated as (using a t-table):

$P-value=P(t$

As the P-value (0) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours.

5 0

3 years ago