Question

分式加减法 先化简 原式=x²-4x+4/x²-4 - x+2/x-2 把x=根下2代入

Answer 1

原式=x²-4x+4/x²-4 - x+2/x-2

=(x-2)^2/(x+2)(x-2)-(x+2)/(x-2)

=(x-2)/(x+2)-(x+2)/(x-2)

=-8x/(x+2)(x-2)

=-8x/(x^2-4)

把x=根下2代入

原式=4√2