一道初一题,计算：x^2+2x+4-（x^3）/(x-2)?[(a^-1)-(b^-1)]/[(a^-2)+(a^-1)(b^-1)+(b^-2)]
网友回答
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)
======以下答案可供参考======
供参考答案1:
原式=[(x-2)(x²+2x+4)-x³]/(x-2)
=(x³-8-x³)/(x-2)
=-8/(x-2)
供参考答案2:
x^2+2x+4-（x^3）/(x-2)
=[(x^2+2x+4)(x-2)-（x^3）]/(x-2)
=-8/(x-2)
=8/(2-x)