Question

I don’t know how to do it

Answer 1

x^2 - 10 + 5

Explanation:

3x^2 - 6x - 7 + -2x^2 - 4x + 12

3x^2 - 6x - 7 - 2x^2 - 4x + 12

Group like terms:

3x^2 - 2x^2 - 6x - 4x - 7 + 12

Add similar elements:

3x^2 - 2x^2 = x^2

x^2 - 6x - 4x - 7 + 12

-6x - 4x = -10x

x^2 - 10x - 7 + 12

-7 + 12 = 5

x^2 - 10 + 5