Answer
$$9x^4+2x^3+11x-6.$$
Work Step by Step
We subtract the $x^4$-terms as follows
$$
7x^4+2x^4=9x^4
$$
then subtract the $x^3$-terms as follows
$$
3x^3-x^3=2x^3
$$
then subtract the $x$-terms as follows
$$
5x+6x=11x
$$
then subtract the constant terms as follows
$$
0-6=-6$$
Hence, the result is
$$9x^4+2x^3+11x-6.$$
