Question

Phân tích các đa thức sau thành nhân tử:

\(e,30x^3-18x^2y-72y+120x\)

\(f,70x-84y+20xy-24y^2\)

Answer 1

\(30x^3-18x^2y-72y+120x\)

= \(6\left(5x^3-3x^2y-12y+20x\right)\)

= \(6\left[x^2\left(5x-3y\right)+4\left(5x-3y\right)\right]\)

= \(6\left(x^2+4\right)\left(5x-3y\right)\)

Answer 2

\(70x-84y+20xy-24y^2\)

= \(2\left(35x-42y+10xy-12y^2\right)\)

= \(2\left[7\left(5x-6y\right)+2y\left(5x-6y\right)\right]\)

= \(2\left(5x-6y\right)\left(7+2y\right)\)