The sum of two numbers is 19 and their difference is 27. What are the numbers?
a+b=19
a-b=27
a+b=19 /-b
a=19 - b
a-b=27 /+b
a=27 + b
19 - b = 27 + b / -27
-8 - b = b / +b
-8 = 2b / /2
-4 = b
a + b = 19
a - 4 = 19 / +4
a = 23
