化简:(x²-2x分之x+2再减去x²-4x+4分之x-1)÷x分之4-x
1个回答

你的表达有问题啊!请注意括号的正确使用,以免造成误解.

[(x+2)/(x^2-2x)-(x-1)/(x^2-4x+4)]÷[(4-x)/x]

={(x+2)/[x(x-2)]-(x-1)/(x-2)^2}[x/(4-x)]

={(x+2)(x-2)/[x(x-2)^2]-x(x-1)/[x(x-2)^2]}[x/(4-x)]

={[(x^2-4)-(x^2-x)]/(x-2)^2}/(4-x)

=(x^2-4-x^2+x)/[(4-x)(x-2)^2]

=-(4-x)/[(4-x)(x-2)^2]

=-1/(x-2)^2.