Question

4) The sum of two numbers is 39. Their
difference is 21. What are the two numbers?

Answer 1

30 and 9

Explanation:

x+y=39 , x-y=21

Solve for x:

x+y=39 , x-y=21

x= 30

Substitute x with 30:

(30)+y=39 , (30)-y=21

Solve for y:

y=9