Question

Given: x + y = 10. If x = -21, what is y?
-31 or 31?

Answer 1

31

Explanation:

-21+y=10

y=10+21

y=31

Answer 2

y = 31

Explanation:

x + y = 10

Let x = -21

-21 + y = 10

Add 21 to each side

-21+21 +y = 10+21

y = 31