Answer:
-8m^2 -2m +17
Step-by-step explanation:
(-6m^2 - 7m + 8) - (2m^2 - 5m - 9)
Distribute the minus sign
(-6m^2 - 7m + 8) - 2m^2 + 5m + 9
I like to line them up vertically
-6m^2 - 7m + 8
- 2m^2 + 5m + 9
---------------------------
[tex](-6m^2-7m+8)-(2m^2-5m-9)\\\\=-6m^2-7m+8-2m^2-(-5m)-(-9)\\\\=-6m^2-7m+8-2m^2+5m+9\qquad\text{combine like terms}\\\\=(-6m^2-2m^2)+(-7m+5m)+(8+9)\\\\=\boxed{-8m^2-2m+17}[/tex]
