Question

The sum of two numbers is 51.

The difference of the same two numbers is 9.

What are the two numbers?

Answer 1

21 and 30

Explanation:

x + y = 51

x - y = 9

add the two equations and y's will cancel out

2x = 42 divide by 2

x = 21 so put 21 in for x in the top equation and solve

21 + y = 51

y = 30