Find the remainder when

a. x³ + 2x² – x + 3 is divided by x – 1

b. x³ – 6x² + 11x – 7 is divided by x – 2

c. x³ – 3x² – 33x + 30 is divided by x + 2

d. 2x³ – x² – 18x + 11 is divided by 2x -1.