如果p(X) = x3 -x2 + 3x + 4 则求出 p(1) 和 p(-2)的值

设： P(x) = x³ + 3x² – 2x + 4

p(-2) = (-2)³ + 3(-2)² – 2(-2) + 4
= -8 + 12 + 4 + 4
= 12

p(1) = (1)³ + 3(1)² – 2(1) + 4
= 1 + 3 – 2 + 4
= 6

p(0) = 0³ + 3(0)² – 2(0) + 4
= 4

p(1) + p(-2) + p(0) = 12 + 6 + 4 = 22