Answer:
heather=26.4yrs
billy= 6.6yrs
Step-by-step explanation:
heather = 4x - 7
bill = x
sum = 33yrs
x + 4x - 7 = 33yrs
5x - 7 = 33
5 5
x - 7 (this seven is only applicable to heather as we took the whole 7 and subtracted it from heather sice it was hers initially, billy will just be 6.6)
= 6.6
heather = 4x - 7
= 6.6 x 4 - 7
=26.4yrs
billy= 6.6yrs