The sum of two numbers is 18 and the difference is 8

x = 13 and y = 5

Step-by-step explanation:

x + y = 18

x - y = 8

Step 1: Find y

x = 18 - y

(18 - y) - y = 8

18 - y - y - 18 = 8 - 18

-2y / - 2 = - 10 / - 2

y = 5

Step 2: Plug into x + y = 18 to get x

x + 5 - 5 = 18 - 5

x = 13

Answer: x = 13 and y = 5