okay so you either add or multiply the ones with the same powers
-3x^4 + 5x^4 = 2x^4
+ 9x^3 (as there are no other ones with the same powers this remains the same
-4x + - 9x (adding a negative is the same as subtracting)
so - 4x - 9x = -13x
4 + - 2 = 4 - 2 = + 2
so 2x^4 + 9x^3 - 13x + 2
the answer is B
