x加1分之一加x减1分之一等于x的二次方减1分之七答案

1/(x+1)+1/(x-1)=7/(x^2-1)(x-1)/[(x+1)(x-1)]+(x+1)/[(x+1)(x-1)]=7/(x^2-1)(x-1)/(x^2-1)+(x+1)/(x^2-1)=7/(x^2-1)[(x-1)+(x+1)]/(x^2-1)=7/(x^2-1)2x/(x^2-1)=7/(x^2-1)2x=7x=7/2演算,x+1、x-1都不等于 0