Answer:
12 and 21
Explanation:
Let the age of Bob is x then the age of Joe is x + 9
Three years ago Bob age is x - 3 and Joe is x + 9 - 3 = x + 6
The sum of their ages is (x - 3) + (x + 6) = 27
x - 3 + x + 6 = 27 Add like terms
2x + 3 = 27 Solve equation
2x = 27 - 3
2x = 24
x = 12
Bob = x =12
Joe = x + 9 = 12 + 9 = 21