Answer:
B
Step-by-step explanation:
Hey There!
To solve this problem we have to combine like terms
[tex]7x^3-6x^3=x^3\\6x^2-8x^2=-2x^2\\-5x+10x=5x\\5-7=-2[/tex]
So our answer would be
[tex]x^3-2x^2+5x-2[/tex] (b)