Answer:
x^2 + 9x - 8
Explanation:
Break the brackets out and you will get:
(12x^2+8x-3)-(11x^2-x+5)
= 12x^2 + 8x -3 - 11x^2 - (-x) - (+5)
= 12x^2 + 8x - 3 - 11x^2 + x - 5
=12x^2 - 11x^2 + 8x + x - 5 - 3
= x^2 + 9x - 8 or x(x+9) -8
You can factorize it even more but it won't factorize much so you can keep it as this equation!
Hope this helped :3