Question

Ethan is 40 years old. His son is 12 years old. How many years ago was Ethan 5 times older than his son?

Answer 1

X=number of years that Ethas was 5 times older than his son.
we suggest this equation:

40-x=5(12-x)
40-x=60-5x
-x+5x=60-40
4x=20
x=20/4=5

answer. 5 years. 

Answer 2

x=number of years that Ethan was 5 times older than his son.

we suggest this equation:

40-x=5(12-x)

40-x=60-5x

-x+5x=60-40

4x=20

x=20/4=5

answer. 5 years.