Subtract the polynomials.
( x^6 -2x^5 –x^3 — 7) – (3x^6 - 3x^5 -2x^ 2 – 5)

-2x^6+x^5-x^3-2+2x^2 Hope that helps!

Step-by-step explanation:  

1. Remove Parentheses x^6-2x^5-x^3-7-3x^6+3x^5+2x^2+5

2. Collect like terms (x^6-3x^6)+(-2x^5+3x^5)-x^3+(-7+5)+2x^2

3. Simplify and your answer would be -2x^6+x^5-x^3-2+2x^2