Question

x的平方减1除以(x减1减x加1分之2x减1),在给x代入你喜欢的数值

Answer 1

原式=(x+1)(x-1)÷{[(x+1)(x-1)-2x+1]/(x+1)}

=(x+1)(x-1)÷[(x²-2x)/(x+1)]

=(x+1)²(x-1)/(x²-2x)

令x=1

原式=2²×0/(1-2)=0