Question

How do you combine like terms in `(r - 3) ( r + 1) + ( r - 3) ( r + 8)`?

Answer 1

`(2r-3)(r+9)`

Explanation:

`(r-3)(r+1)+(r-3)(r+8)`

`:.=(r^2-2r-3)+(r^2+8r-24)`

`:.=2r^2+6r-27`

`:.=(2r-3)(r+9)`