Question

第三题， 化简求值那道。谢谢～

Answer 1

化简：
=X-3）/[-2)(x+2)/(x+2)-5/(x+2)]
=1/2(x+3)
然后将X代入式子求解

Answer 2

x＝sin60°-3,即2(x+3)＝2sin60°＝√3,

∴[(x-3)/(4+2x)]÷[(x-2)-5/(x+2)]

＝[(x-3)/2(x+2)]÷[((x²-4)-5)/(x+2)]
＝[(x-3)/2(x+2)]·[(x+2)/(x²-9)]
＝(x-3)/[2(x+3)(x-3)]
＝1/[2(x+3)]
＝1/√3
＝√3/3。