Question

(1+2x-4/x2-x-2)÷x+3/x²-1 化简 x=根号3 先化简再求值

Answer 1

=(x²-x-2+2x-4)/(x²-x-2)×(x²-1)/(x+3)

=(x²+x-6)/(x-2)(x+1)×(x+1)(x-1)/(x+3)

=(x+3)(x-2)/(x-2)(x+1)×(x+1)(x-1)/(x+3)

=x-1

当x= √3时

原式=x-1=√3-1