Question

The sum of two numbers is 15. The difference of he same two numbers is 3. What are the two numbers?

Answer 1

x+y =15

x-y = 3

add the two equations

2x = 18

divide by 2

x = 9

x + y = 15

9 + y =15

subtract 9

y = 9

The two numbers are 6 and 9