Question

先化简再求值x减二分之x方加二x-x减一分之x方加四x+4括号除以x加二分之x减四

先化简,再求值：（x+2/x^2-2x-x-1/x^2-4x+4)除以x^2-16/x^2+4x,其中x=2+根号

Answer 1

根号几啊?
原式=[(x+2)/x(x-2)-(x-1)/(x-2)²]÷(x+4)(x-4)/x(x+4)
=(x²-4-x²+x)/x(x-2)²*x/(x-4)
=(x-4)/x(x-2)²*x/(x-4)
=1/(x-2)²