Answer:
[tex]\large\boxed{(-5x^2-3x-7)+(-2x^3+6x^2-8)=-2x^3+x^2-3x-15}[/tex]
Step-by-step explanation:
[tex](-5x^2-3x-7)+(-2x^3+6x^2-8)\\\\=-5x^2-3x-7-2x^3+6x^2-8\qquad\text{combine like terms}\\\\=-2x^3+(-5x^2+6x^2)-3x+(-7-8)\\\\=-2x^3+x^2-3x-15[/tex]
