Question

The sum of two numbers is 40, and their difference is 8. Find the numbers.

Answer 1

$x+y=40\\ x-y=8\\ -----\\ 2x=48\\ x=24\\\\ 24+y=40\\ y=16$

Answer 2

   a - b = 8
+ a + b = 40   
   2a = 48
     a = 24

a - b = 8
24 - b = 8
b = 16