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2 years ago

Expand 3a(2b+c) .............

Mathematics

1 answer:

777dan777 [17]2 years ago

4 0

Answer:

We know that the distributive property says this:

a(b+c) = ab + ac

If we apply this to our case, we can put

3a(2b+c) = 3a * 2b + 3a * c

When we multiply numbers and letters, we should multiply both of them:

3a * 2b + 3a * c = 3*2*a*b + 3*a*c = 6ab +3ac

We can use this when we find a number multiplied by a parenthesis..

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Please help i know it a lot but please

blsea [12.9K]

Answer:

I have no clue

Step-by-step explanation:

I'm in middle school I don't know

6 0

2 years ago

To estimate the number of people in Springfield, population 10,000, who have a swimming pool in their backyard, 250 people were

Andrei [34K]

Answer:

2400 people

Step-by-step explanation:

Let x be the number of people who had a swimming pool in the population of 10,000,

Thus, the ratio of people who had swimming pool to the total population = $\frac{x}{10000}$

Since, out of 250 people 60 had swimming pool,

So, the ratio of the people who had swimming pool to the total population = $\frac{60}{250}$

$\because \frac{x}{10000}=\frac{60}{250}$

$\implies 250x=600000$

$\implies x=\frac{600000}{250}=2400$

Hence, 2400 people in the city might one expect to have a swimming pool.

First option is correct.

8 0

3 years ago

Identify the exact value of 157.5°

steposvetlana [31]

exact value of sin 157.5 without using a calculator
sin(157.5)=sin(315/2)
Identity: sin(x/2)=±√[(1-cosx)/2]
select positive identity since 175 is in the 2nd quadrant where sin>0
sin(315/2)=√[(1-cos315)/2]

cos 315=cos45 in quadrant IV=√2/2
sin(315/2)=√[(1-√2/2)/2]=√[(2-√2)/4]=√(2-√2)/2
sin(157.5)=√(2-√2)/2
check using calculator:
sin157.5º≈0.382...
√(2-√2)/2≈0.382...

8 0

3 years ago

A supervisor records the repair cost for 25 randomly selected dryers. A sample mean of $93.36 and standard deviation of $19.95 a

Feliz [49]

Answer:

The 98% confidence interval for the mean repair cost for the dryers is (83.4161, 103.3039).

Step-by-step explanation:

We have a small sample size n = 25, $\bar{x} = 93.36$ and s = 19.95. The confidence interval is given by $\bar{x}\pm t_{\alpha/2}(\frac{s}{\sqrt{n}})$ where $t_{\alpha/2}$ is the $\alpha/2$ th quantile of the t distribution with n - 1 = 25 - 1 = 24 degrees of freedom. As we want the 98% confidence interval, we have that $\alpha = 0.02$ and the confidence interval is $93.36\pm t_{0.01}(\frac{19.95}{\sqrt{25}})$ where $t_{0.01}$ is the 1st quantile of the t distribution with 24 df, i.e., $t_{0.01} = -2.4922$ . Then, we have $93.36\pm (-2.4922)(\frac{19.95}{\sqrt{25}})$ and the 98% confidence interval is given by (83.4161, 103.3039).

3 0

2 years ago

Read 2 more answers

Prove that there are no positive perfect cubes less than 1000 that are the sum of the cubes of two positive integers?

valentina_108 [34]

The perfect cubes less than 1000 are:

1^3 = 1 
2^3 = 8 
3^3 = 27 
4^3 = 64 
5^3 = 125 
6^3 = 216 
7^3 = 343 
8^3 = 512 
9^3 = 729

so
2^3 = 8 could only be 1 + 1, but this is 2, not 8. 
3^3 = 27 could be 1 + 1, 1 + 8 or 8 + 8, but all of these are too small 
4^3 = 64 could be 1 + 1, 1 + 8, 1 + 27, 8 + 8, 8 + 27, 27 + 27.
 general proof that a^3 + b^3 = c^3 holds for no positive integers
hope it helps

6 0

3 years ago

Expand 3a(2b+c) .............​

Expand 3a(2b+c) .............