化简3x^2-9x-12/x^2+2x+1 xy-x-y+1/y^2-2y+1

显示全部楼层 · 2011-10-20 10:32:38

(2)①xy-x-y+1 提取公因子 x 得 x（y-1）-y+1
变式
得 x（y-1）+（y-1）提取公因式（y-1）得 xy-x-y+1=（x+1）*（y-1）②y^2-2y+1根据十字相乘法将式子进行如下拆分 y - 1

y - 1所以 y^2-2y+1=（y-1）^2所以(xy-x-y+1)/(y^2-2y+1 )
=[（x+1）*（y-1）] /[（y-1）^2]
=（x+1)/(y-1)...

千问 · 2011-10-20 10:32:38

解：3x^2-9x-12/x^2+2x+1=3(x^2-3x-4)/(x+1)^2=3(x-4)(x+1)/(x+1)^2=3(x-4)/(x+1)xy-x-y+1/y^2-2y+1=xy-y-x+1/(y-1)^2=y(x-1)-(x-1)/(y-1)^2=(x-1)(y-1)/(y-1)^2=(x-1)/(y-1)...

千问 · 2011-10-20 10:32:38

(3x^2-9x-12)/(x^2+2x+1)= 3(x^2-3x-4)/(x+1)^2= 3(x-4)(x+1)/(x+1)^2= 3(x-4)/(x+1)(xy-x-y+1)/(y^2-2y+1)=(x-1)(y-1)/(y-1)^2=(x-1)/(y-1)...

千问 · 2011-10-20 10:32:38

(3x^2-9x-12)/(x^2+2x+1)= 3(x^2-3x-4)/(x+1)^2= 3(x-4)(x+1)/(x+1)^2= 3(x-4)/(x+1)...