add

(3c^4-2c^3+11c-9)+(c^5+7c^3+4c^2-3c+6)+(-6c^4+c^2-5c-5)

Add up the terms with the same power of c, and add up the constants. Then write them down as a new polynomial.

c^5 -3c^4 + ___c^3 + ___c^2 + ___c -8

Fill in the blanks.