First of all, 5x2 + 10x -75/(x – 5) should be written as 5x^2 + 10x -75/(x – 5).
Then you have:
75
5x^2 + 10 x - ---------
x-5
This mixed expression has the denominator x-5. Rewriting it again,
5x^3 - 25x^2 + 10x^2 - 50x - 75
------------------------------------------
x-5
Complete this work by combining all like terms. -25x^2+10x^2 = -15x^2 would be an example of that.
