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2 years ago

The sum of 12 and a certain number is equal to the product of 3 and the number

Mathematics

1 answer:

german2 years ago

3 0

Answer:

Read the explanation!

Step-by-step explanation:

Let the "certain number" be $x$ .

( $*$ is a symbol for multiplication).

Create a few equations and expressions:

The sum of 12 and a certain number: $12 + x$

The product of 3 and the number: $3 *x = 3x$

The sum of 12 and a certain number is equal to the product of 3 and the number:

$12 + x$ = $3x$

Solve!

12=3x-x

12=2x

x=6

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2 years ago

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RoseWind [281]

Answer:

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Step-by-step explanation:

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2x + 3y = 30

You can do any math operation to each side of the equal sign as long as you do the same operation to both sides.

change x + y = 4 to x = 4 - y

Now substitute (4 - y) into the second equation, in place of x.

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multiply the 2(4-y) part:

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Check:

x + y = 4

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4 = 4 (this checks)

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PS: you could have solved for y first if you had wanted to. The results would be the same.

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3 years ago

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