Question 62953
The given question is:

(7x^3 - 2x^2 + 4x - 1) - (9x^3 - 4x^2 + x - 3) + (2x^3 - 2x^2 - 3x - 2)

First we remove the parenthesis.

==> 7x^3 - 2x^2 + 4x - 1 - 9x^3 + 4x^2 - x + 3 + 2x^3 - 2x^2 - 3x - 2

Now we add the like terms , that is the terms which have the same variable raised to the same power.

==> (7x^3 - 9x^3 + 2x^3) + (-2x^2 + 4x^2 - 2x^2) + (4x - x - 3x) + (-1 + 3 - 2)

==> 0  + 0 + 0 + 0

= 0


Good Luck!!!