Phân tích thành nhân tử

\(2x^2-5xy-3y^2\)

We believe that it was you who robbed the post office.

( up)
==> We believe that.......................................the post office.

Phân tích thành nhân tử

\(x^2\left(y-z\right)+y^2\left(z-x\right)+z^2\left(x-y\right)\)

CM : \(x^4+2012x^2-2011x+2012>0\)

Phân tích thành nhân tử

\(\left(a+b+c\right)^2+\left(a-b+c\right)^2-4b^2\)