The we of a father is 2 less than 7 times the age of his son. In 3 years, the sum of their ages will be 52. If the son's present age is s years, which equation models this situation?

Fathers age = F

F = S * 7 - 2

F + 3 + S + 3 = 52

F + S + 6 = 52

F + S = 46

Replace F in F + S, with our previous equation, so that we can only have one type of letter on any side at any given time

so in this case we have, (S * 7 - 2) + S = 46

We can remove the brackets, as they are not necessary in this case

S * 7 - 2 + S = 46

Remove - 2 by adding 2 on both sides

S * 7 + S = 48

Simplify

S * 8 = 48

divide both sides by 8

S * 8/8 = 48/8

S = 6

F + S = 46

F + 6 = 46

F = 40