Question 4206
Remove the parentheses, remembering that a negative of a negative is a positive.

{{{(4x^3  - 9x + 15) - (-2x^3 +  4x^2 + 7x)}}}

{{{4x^3  - 9x + 15 + 2x^3 -  4x^2 - 7x}}}


Combine like terms:
{{{6x^3  - 4x^2 - 16x + 15}}}


By the way, what is this about "Give answer with only positive exponents."  If the problem is copied correctly how could it be anything else? 


R^2 at SCC