Amother is three times as old as her son. eight years ago, she was 4 more than five times the age of her son. how old is the mother now?

M=mother age
s=son age

mother is 3 times son
m=3s

8 years ago (m-8 and s-8)
mother was 4 more than 5 times son
m-8=4+5(s-8)
m-8=4+5s-40
m-8=5s-36

m=3s
sub 3s for m
3s-8=5s-36
minus 3s both sides
-8=2s-36
add 36 to boh sides
28=2s
divide by 2 both sides
14=s

sub back
m=3s
m=3(14)
m=42

mother=42

What am i doing here. add?

Oh i'm sorry. didn't see the options