say Steve is x ,then jenny will be x + 12
five years ago Steve's age was x - 5 and Jenny's age was x + 12 - 5= x + 7
since jenny was four times Steve's age 5 years ago the equation will be
x + 7 = 4(x - 5)
= x + 7 = 4x - 20
putting like terms together, we will have
4x - x = 20 + 7
= 3x = 27
this means 3x ÷ 3= 27 ÷ 3
x = 9
this means Steve is 9 years old and Jenny is 21 years old
