它的加减法类似于分数的加减法:先通分成同分母后,分母不变,分子相加减。即:a/b±c/d=ad/bd±cb/bd=(ad±bc)/bd。结果能约分的要约分。如:1/(x-1)-2/(x+1)=( x+1)/(x-1)(x+1)-2(x-1)/(x+1)(x-1)=((x+1)-2(x-1))/(x+1)(x-1)=(3-x)/(x+1)(x-1)。
它的加减法类似于分数的加减法:先通分成同分母后,分母不变,分子相加减。即:a/b±c/d=ad/bd±cb/bd=(ad±bc)/bd。结果能约分的要约分。如:1/(x-1)-2/(x+1)=( x+1)/(x-1)(x+1)-2(x-1)/(x+1)(x-1)=((x+1)-2(x-1))/(x+1)(x-1)=(3-x)/(x+1)(x-1)。