Question

when x2+3x-4 is subtracted from x (x2+3x-2) what is the difference

Answer 1

I'm assuming this is x^2 + 3x - 4 and x(x^2 + 3x - 2)

1.) First distribute x(x^2 + 3x - 2) to get x^3 + 3x^2 - 2x.

2.) Because you are subtracting all the terms from x^3 + 3x^2 - 2x, it's the same thing as distributing -1 to x^2 + 3x - 4 and then adding it to x^3 + 3x^2 - 2x.

3.) -1(x^2 + 3x - 4) = -x^2 - 3x + 4

4.) Add (x^3 + 3x^2 - 2x) + (-x^2 - 3x + 4)

5.) x^3 + 2x^2 - 5x + 4 is your final answer.

Answer 2

Assuming that the problem is  (x^2+3x-4) - x(x^2+3x-2) then this would be simple.. simplifying XD
here is the work for you:
(x^2+3x-4) - x(x^2+3x-2)
(x^2+3x-4) - (x^3+3x^2-2x)
Final Answer: -x^3-2x^2+5x-4