6x^2-13x+6 2x^2-8xy+8y^2-11x+22y+15 因式分解

6x²-13x+6=(2x-3)(3x-2
2x²-8xy+8y²-11x+22y+15
=2(x²-4xy+4y²)-11(x-2y)+15
=2(x-2y)²-11(x-2y)+15 相当于2a²-11a+15
=[2(x-2y)-5][(x-2y)-3]
=(2x-4y-5)(x-2y-3)

十字相乘
1原式=（2x-3）^2
2原式=（x-2y-3）（2x-4y-5）