Answer:
= - x^2 + 4x - 14
Step-by-step explanation:
(2x^2+6x−7)−(3x^2+3x−1)+(x−8)
= (2x^2+6x−7 ) −3x^2 -3x +1 + (x−8)
= (2x^2+6x−7 ) −3x^2 -3x +1 + x−8
= (2x^2+6x−7 ) −3x^2 -2x - 7
= 2x^2+6x−7 −3x^2 -2x - 7
= 2x^2+6x−7 −3x^2 -2x - 7
= - x^2 + 4x - 14