\(12x^2y-18xy^2-30y^3\)
\(=12x^2y+12xy^2-30xy^2-30y^3\)
\(=-2x\left(-6y^2-6xy\right)-5y\left(-6xy-6y^2\right)\)
\(=\left(-6y^2-6xy\right)\left(-2x-5y\right)\)
\(=-6y\left(x+y\right)\left(-2x-5y\right)\)
12x2y - 18xy2 - 30y3
= 12x2y - 18yy - 30yy2
= 2.6x2y + 3.6yy + 5.6yy2
= 6y.(2x2 - 3xy + 5y2)
= 6y.(x + y)(2x - 5y)