Solution:

Since formatting the solution on this text box is pretty difficult, the solution will be line per line:

-12x3 - 8x2 + 17x ÷ 4x2 - 4x + 1 = -3x ---> 1st term

-12x3 - 8x2 + 17x - (-12x3 + 12x2 - 3x) = -20x2 + 20x

-20x2 + 20x - 5 ÷ 4x2 - 4x + 1 = -5 ---> second term

-20x2 + 20x - 5 - (-20x2  + 20x - 5) = 0

So the answer is: -3x - 5