Question

Phân tích đa thức thành nhân tử:

7x^3y-3xyz-21x^2+9z

Answer 1

\(7x^3y-3xyz-21x^2+9z\)

\(=\left(7x^3y-21x^2\right)-3xyz+9z\)

\(=7x^2\left(xy-3\right)-3z\left(xy-3\right)\)
\(=\left(7x^2-3z\right)\left(xy-3\right)\)
 

Answer 2

\(7x^3y-3xyz-21x^2+9z\)

\(=\left(7x^3y-21x^2\right)+\left(-3xyz+9x\right)\)

\(=7x^2\left(xy-3\right)-3z\left(xy-3\right)\)

\(=\left(xy-3\right)\left(7x^2-3z\right)\)