Simplify:

x4 – 2x3 + 3x2 – 4x – x3 + 2x2 – 3x + 4 – (2x3 – 2x2 + 2x – 3x2 + 3x – 3)

= x4 – 3x3 + 5x2 – 7x + 4 – 2x3 + 5x2 – 5x + 3


= x4 – 5x3 + 10x2 – 12x + 7


32