Question

初三数学题！！（急~！！！！！！！！！）

先化简后求值：
题在图片上，其中x=tan60°-1

Answer 1

x=√3-1

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

Answer 2

[1/(x+2)-1]/[(x²+2x+1)/(x²-4)]
=(1-x-2)/(x+2)/[(x+1)²/(x+2)/(x-2)]
=-(x+1)(x+2)(x-2)/[(x+2)(x+1)²]
=-(x-2)/(x+1)
x=√3-1
原式=-(√3-1-2)/(√3-1+1）
=-（√3-3）/√3
=√3-1

Answer 3

就是这样 之后把x=tan60°-1带入 得原式答案为√3-1

Answer 4

(1/%3 +1 -1)(-2%3/3)
=%3-1
(%是根号）