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2 years ago

Three-sevenths of a number is 21. Find the number

2 answers:

7 0

You can set up a proportion that looks like 3/7 = x/21. X being the number that you are trying to find. Seven goes into 21 three times. So multiply 3 also by that 3 to get 9. So three sevenths of twenty-one is 9.

Softa [21]2 years ago

6 0

Answer:

the answer is 49

Step-by-step explanation:

The question is asking what the original number is. So its not 9. If you do a inverse operation which is 2 divided by 3/7 you get 49. To check your work if you multiply 49 by 3/7 you get 21.

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Subtract the following polynomials

Olegator [25]

Answer:

1. (q² + 8) - (4q² + 1)

Simplify each term.

q²+8−4q²−1

Simplify by adding terms.

−3q²+7

2. (3x + 7x² - 6) - (5x² + x + 9)

Simplify each term.

3x+7x²−6−5x²−x−9

Simplify by adding terms.

Tap for more steps...

2x²+2x−15

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

Question one please and show work

Ilya [14]

Answer:

Step-by-step explanation:

c is correct bcause if you work out a it says is less than. then the gcf is 2 and 3 but do 2 times 3

6 0

3 years ago

Read 2 more answers

How do I solve this equation n^2=18n+40.

Readme [11.4K]

Answer:

n = 20 or n = -2

Step-by-step explanation:

Solve for n over the real numbers:

n^2 = 18 n + 40

Subtract 18 n + 40 from both sides:

n^2 - 18 n - 40 = 0

The left hand side factors into a product with two terms:

(n - 20) (n + 2) = 0

Split into two equations:

n - 20 = 0 or n + 2 = 0

Add 20 to both sides:

n = 20 or n + 2 = 0

Subtract 2 from both sides:

Answer: n = 20 or n = -2

3 0

3 years ago

A box is x to inches high,(2x+3)inches wide, and (2x+5) of inches long. In terms of x, what is the volume (v) of the box?

Advocard [28]

Answer:

The volume of the box is $V=(4x^3+16x^2+15x)\ in^3$

Step-by-step explanation:

we know that

The volume of the box is equal to

$V=LWH$

where

L is the length of the box in inches

W is the width of the box in inches

H is the height of the box in inches

we have

$L=(2x+5)\ in\\W=(2x+3)\ in\\H=x\ in$

substitute in the formula

$V=(2x+5)(2x+3)x$

$V=(4x^2+6x+10x+15)(x)$

$V=(4x^2+16x+15)(x)$

$V=(4x^3+16x^2+15x)\ in^3$

6 0

2 years ago

one days discharge at its mouth, 3 trillion gallons, could supply all of country A’s household for 5 months. how much water an a

serious [3.7K]

let's use engineering notation for the sake of brevity.

1 trillion is 1,000,000,000,000, or just 1E12, twelve zeros.

1 million is then 1E6, six zeros.

we know the discharge for one day is 3E12 gallons, and that'd do just fine for country A for 5 months. How many gallons in 1 month only?

$\bf \begin{array}{ccll} gallons&months\\ \cline{1-2} 3E12&5\\ x&1 \end{array}\implies \cfrac{3E12}{x}=\cfrac{5}{1}\implies 3E12=5x \\\\\\ \cfrac{3E12}{5}=x\implies 6E11=x\implies 600000000000=x$

if there are 200million inhabitants in A, namely 200E6 or 2E8 inhabitants, how many gallons per inhabitant from all those 6E11 gallons?

$\bf \begin{array}{ccll} gallons&households\\ \cline{1-2} 6E11&2E8\\ x&1 \end{array}\implies \cfrac{6E11}{x}=\cfrac{2E8}{1}\implies 6E11=2E8x \\\\\\ \cfrac{6E11}{2E8}=x\implies \cfrac{600000000000}{200000000}=x\implies 3000=x$

5 0

3 years ago