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