Bài 2 :
Câu a : \(10x^3y^3-15x^2y^4+20x^3=5x^2\left(2xy^3-3y^4+4x\right)\)
Câu b : \(9x^3-18x^2y+9xy^2=9x\left(x^2-2xy+y^2\right)=9x\left(x-y\right)^2\)
Câu c : \(9x^2+6x+1-25y^2=\left(3x+1\right)^2-\left(5y\right)^2=\left(3x+5y+1\right)\left(3x-5y+1\right)\)
Câu d : \(x^2-3x-18=\left(x^2+3x\right)-\left(6x+18\right)=x\left(x+3\right)-6\left(x+3\right)=\left(x+3\right)\left(x-6\right)\)