Question

[vu thanh trung]

Bài 1: Phân tích các đa thức sau thành nhân tử
a) 5x2 - 20 b)x3 - x2 + 3x - 3
c) 3x2 - 12 d) x3 +2x2 - 3x - 6

Answer 1

[Nguyễn Thái Thịnh]

\(a,5x^2-20=5\left(x^2-4\right)=5\left(x-2\right)\left(x+2\right)\)

\(b,x^3-x^2+3x-3=x^2\left(x-1\right)+3\left(x-1\right)=\left(x-1\right)\left(x^2+3\right)\)

\(c,3x^2-12=3\left(x^2-4\right)=3\left(x-2\right)\left(x+2\right)\)

\(d,x^3+2x^2-3x-6=x^2\left(x+2\right)-3\left(x+2\right)=\left(x+2\right)\left(x^2-3\right)=\left(x+2\right)\left(x-\sqrt{3}\right)\left(x+\sqrt{3}\right)\)