Question

I feel like I did something wrong can somebody confirm the answer and how to do this:

-3x^2+(15x^2)

Answer 1

Since both have the variable (x) to the same power (2) we simply add the two coefficients together (-3+15) so we get 12x^2

Answer 2

12x^2

if you take away the x^2 on either side do -3 + 15 to get twelve then add the x^2 each side