Question

How old is david if his age 6 years from now will be twice his age 7 years ago?

Answer 1

Let's say David's age right now is x years
x + 6 = 2(x - 7)
x + 6 = 2x - 14
x = 20
Therefor David is 20 years old

Answer 2

X-6=2x-14
x=20
Dave is 20 years old 
hope this helped