Cho hai đa thức:P(x) = 2x^3 – 3x^2 + x;Q(x) = x^3 – x^2 + 2x + 1.Tính P(x) + Q(x); P(x) – Q(x).

P(x) + Q(x) = (2x³ – 3x² + x) + (x³ – x² + 2x + 1)

= 2x³ – 3x² + x + x³ – x² + 2x + 1

= 3x³ – 4x² + 3x + 1

P(x) – Q(x) = (2x³ – 3x² + x) – (x³ – x² + 2x + 1)

= 2x³ – 3x² + x – x³ + x² – 2x – 1

= x³ – 2x² – x – 1.