Can you help me combine the expression into a single fraction?

Question

(t^2-1)/(t^2+7t+10) - (2t+4)/(t^2-t-6)

and

(3a-1)/(2a+6) - 7a/(a^2+7a+12)

Thanks!

Answer 1

(t^2-1)/(t^2+7t+10) - (2t+4)/(t^2-t-6)

factor the denominators first
(t^2-1)/(t+2)t+5) - (2t+4)/(t-3)(t+2)

LCD is (t+2)(t+5)(t-3)

Now, can you combine over the LCD?