Question

How do you simplify `(a^2-9)/a^2 * (a^2-3a)/(a^2+a-12)`?

Answer 1

You first factorise, and then see if you can cancel.

Explanation:

`=((a+3)(a-3))/(a*a)` `*(a(a-3))/((a-3)(a+4))`

`=(a(a+3)(a-3)(a-3))/(a*a(a-3)(a+4))`

`=(cancela(a+3)cancel((a-3))(a-3))/(cancela*acancel((a-3))(a+4))`

`=(a^2-9)/(a^2+4a)`