What is the difference when 2x^3+x-5 is subtracted from 6x^3-x-^2+4x+8?

Subtract the x³'s from the x³'s, the x²'s from the x²'s, the x's from the x's, and the constants from the constants.

Here is 6x³-x²+4x+8 minus 2x³+x-5.
Any numbers with only one value have a 1 added to them and any numbers with no value have a 0 added to them as placeholders.
Notice how I have changed every sign on 2x³+x-5 so that we do not forget we are subtracting every term. The double negative becomes a positive, thus the +5.



There is our answer, 4x³ - x² + 3x + 11.