Answer:
-12x^2-5x-8
Step-by-step explanation:
-12x^2 -5x -8
(-9x^2 +3x -8) -(3x^2 +8x) . . . . show the subtraction
= -9x^2 +3x -8 -3x^2 -8x . . . . . eliminate parentheses
= x^2(-9-3) +x(3-8) +(-8) . . . . . . collect terms
= -12x^2 -5x -8
