Question

How do you simplify `(r^2 - 3rs + 5s^2) - 2(-2r^2 - 3rs - 5s^2)`?

Answer 1

`5r^2+3rs+15s^2`

Explanation:

Expanding we get

`r^2-3rs+5s^2+4r^2+6rs+10s^2`=
`5r^2+3rs+15s^2`