-4x + 6x^2 + 5x

A: 7x^3
B: 6x^2 + 9x
C: 6x^2 - 9x
D: 6x^2 + x

This is for 7th grade Unit 5 Lesson 1: Polynomials and Properties of Exponents.
If you could give the answers to the other questions too that would be awesome, thanks!

well, 5-4 = 1, so ...