x^2+2x+4-(x^3)/(x-2)
=(x-2)(x²+2x+4)/(x-2)-x³/(x-2)
=(x³-8)/(x-2)-x³/(x-2)
=-8/(x-2)
=8/(2-x)
(a^-1)-(b^-1)/(a^-2)+(a^-1)(b^-1)+(b^-2) 分子分母同时乘以a²b²
=(ab²-a²b)/(b²+ab+a²)[(a^-1)-(b^-1)]/[(a^-2)+(a^-1)(b^-1)+(b^-2)](a^-1)-(b^-1)/(a^-2)+(a^-1)(b^-1)+(b^-2)分子分母同时乘以a²b²=(ab²-a²b)/(b²+ab+a²) 不是给你做了吗?怎么还要追问这题请采纳,谢谢