b) x2-3x+xy-3y
=\(\left(x^2+xy\right)-\left(3x+3y\right)\)
=\(x\left(x+y\right)-3\left(x+y\right)\)
=\(\left(x-3\right)\left(x+y\right)\)
c) x2-y2-4x+4
=(\(x^2-4x+4\))\(-y^2\)
=\(\left(x-2\right)^2\) \(-y^2\)
=(\(x-y-2\)) \(\left(x+y-2\right)\)
a)6x3y-9x2y2+3xy
=\(3xy\left(2x^2-3xy+1\right)\)
a: \(6x^3y-9x^2y^2+3xy\)
\(=3xy\left(2x^2-3xy+1\right)\)
b: \(x^2-3x+xy-3y\)
\(=x\left(x-3\right)+y\left(x-3\right)\)
\(=\left(x-3\right)\left(x+y\right)\)
c: \(x^2-y^2-4x+4\)
\(=\left(x-2\right)^2-y^2\)
\(=\left(x-2-y\right)\left(x-2+y\right)\)