Question

初三一道计算题,先化简、再求值先化简,后求值:x+1分之x+2÷x²-1分之x-1,其中x=（根号3）-2,要

Answer 1

(x+2)/(x+1)÷(x-1)/(x^2-1) = (x+2)/(x+1)×(x^2-1)/(x-1)

= (x+2)/(x+1)×[(x+1)(x-1)]/(x-1)

= (x+2)/(x+1)×(x+1)

= x+2

把x=√3 －2代入,原式＝ x+2 = √3 －2 +2 =√3