Cho hai đa thức:P(x) = x^3 – 2x^2 + x – 5Q(x) = −x^3 + 2x^2 + 3x – 9Tính P(x) + Q(x); P(x) – Q(x)
Giải thích
P(x) + Q(x) = (x3 – 2x2 + x – 5) + (−x3 + 2x2 + 3x – 9)
= x3 – 2x2 + x – 5 − x3 + 2x2 + 3x – 9
= 4x – 14
P(x) – Q(x) = (x3 – 2x2 + x – 5) + (−x3 + 2x2 + 3x – 9)
= x3 – 2x2 + x – 5 + x3 – 2x2 – 3x + 9
= 2x3 – 4x2 – 2x + 4