Answer:
C.
Explanation:
Simply add the two functions.
5x³+2x²-7x+4
+ 3x-7
Everything with an exponent stays the same because there is nothing else with those exponents in the other function. So all you're doing is adding the -7x+4 and 3x -7.
-7x+3x = -4x
4 - 7 = -3
That leaves you with answer C:
5x³+2x²-4x-3