Question

Phân tích đa thức thành nhân tử

a, 4x^2-5x+1 d, 4x^2-4x+3

b, 7x-3x^2-2 e, 3x^2-8x+4

c, x^2-6x+8 f, x^2-21x+38

Answer 1

a, 4x²-5x+1 = 4x²-4x-x+1= 4x(x-1)-(x-1)=(x-1)(4x-1)

c, x² -6x +8 = x²-2x-4x+8=x(x-2)-4(x-2)=(x-2)(x-4)

e, 3x² -8x+4 =3x²-6x-2x+4=3x(x-2)-2(x-2)=(x-2)(3x-2)

f,x² -21x+38=x²-2x-19x+38=x(x-2)-19(x-2)=(x-2)(x-19)

Answer 2

a) \(4x^2-5x+1=4x^2-x-4x+1\)

\(=x\left(4x-1\right)-\left(4x-1\right)=\left(4x-1\right)\left(x-1\right)\)

b) \(7x-3x^2-2=-3x^2+7x-2\)

\(=-3x^2+x+6x-2=-x\left(3x-1\right)+2\left(3x-1\right)\)

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

c) \(x^2-6x+8=x^2-2x-4x+8\)

\(=x\left(x-2\right)-4\left(x-2\right)=\left(x-2\right)\left(x-4\right)\)

d) \(4x^2-4x+3=4x^2-2x-6x+3\)

\(=2x\left(2x-1\right)-3\left(2x-1\right)=\left(2x-1\right)\left(2x-3\right)\)

e) \(3x^2-8x+4=3x^2-6x-2x+4\)

\(=3x\left(x-2\right)-2\left(x-2\right)=\left(x-2\right)\left(3x-2\right)\)

f) \(x^2-21x+38=x^2-2x-19x+38\)

\(=x\left(x-2\right)-19\left(x-2\right)=\left(x-19\right)\left(x-2\right)\)