Answer:
x^2 - 10 + 5
Step-by-step 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
