Answer:
[tex]\large\boxed{-8x^2-(8x-6x^2-8x)-[7-(-8x-7)]=-2x^2-8x-14}[/tex]
Step-by-step explanation:
[tex]-8x^2-(8x-6x^2-8x)-[7-(-8x-7)]\\\\=-8x^2-8x-(-6x^2)-(-8x)-[7-(-8x)-(-7)]\\\\=-8x^2-8x+6x^2+8x-(7+8x+7)\\\\=-8x^2-8x+6x^2+8x-7-8x-7\qquad\text{combine like terms}\\\\=(-8x^2+6x^2)+(-8x+8x-8x)+(-7-7)\\\\=-2x^2-8x-14[/tex]
