12/x^2-9+2/3-x 分式计算

问题描述:

12/x^2-9+2/3-x 分式计算

原式=12/(x+3)(x-3)-2(x+3)/(x+3)(x-3)
=(12-2x-6)/(x+3)(x-3)
=-2(x-3)/(x+3)(x-3)
=-2/(x+3)