How do I simplify these problems

(9a^2)(b) / 45ab^2

(b + 4)^2 / (b^2) + 7b + 12

And the last one, which I think I understand...

10y - 30 / (y^2) - 1

Which I have as...

10(y - 3) / y(y - 1) = 10(-2) / y

But if someone could help me just get started on the other two, I'd appreciate it!

a) (9a^2)(b) / 45ab^2 = a/5b

b) Assuming it is
(b + 4)^2 / (b^2 + 7b + 12) =
(b+4)^2/(b+4)(b+3) =
(b+4)/(b+3)

c) Assuming it is
10y - 30 / (y^2 - 1)
10(y-3)/(y+1)(y-1)