化简求值(x-2-12/x-2)/4-x/x+2,其中x=-4+根号3

问题描述:

化简求值(x-2-12/x-2)/4-x/x+2,其中x=-4+根号3

{(x-2)-12/x-2}/(4-x)/(x+2)
=(x-14)/(x-2)*(x+2)/(4-x)
=(x-14)(x+2)/(x-2)(4-x),x=-4+√3
=(√3-18)(√3-2)/(√3-6)(8-√3)
=(39-20√3)/(14√3-51)