Question

The sum of an unknown number and fifteen is decreased by eight. The result is two.

Answer 1

-5

Explanation:

Let's call this unknown number x.

Then (x+15)-8=2. Therefore, x=2+8-15 = -5.

Answer 2

n+15 -8 =2

n=-5

Explanation:

Let n be the unknown number

sum of an unknown number and fifteen

n+15

is decreased by eight

n+15 -8

The result is two.

n+15 -8 =2

Combine like terms

n +7 =2

Subtract 7 from each side

n+7-7=2-7

n=-5