15x^2-20xy-x+8y-2
问题描述:
15x^2-20xy-x+8y-2
答
15x^2-20xy-x+8y-2
=(15x²-x-2)-(20xy+8y)
=(3x+1)(5x-2)-4y(5x-2)
=(5x-2)(3x+1-4y)
=(5x-2)(3x-4y+1)
也可以把原式化为15x²+(-20y-1)x+8y-2再用十字相乘法,求根法分解.