x² - x + 4x - 4 → D
Expand using the FOIL method
F → multiply First terms → x and x = x²
O → multiply the Outer terms → - 1 and x = - x
I → multiply the Inner terms → 4 and x = 4x
L → multiply the last terms → 4 and - 1 = - 4
(x + 4)(x - 1) = x² - x + 4x - 4