x=-8sin30度+tan60度
=-8×1/2+√3
=-4+√3
(x-2-12/x+2)除4-x／x+2
=[(x-2)(x+2)-12-4x]/[4(x+2)]
=(x²-4-12-4x)/[4(x+2)]
=(x²-4x-16)/[4(x+2)]
=[(x-2)²-20]/[4(x+2)]
=[(-6+√3)²-20]/(-8+4√3)
=(36+3-12√3-20)/(-8+4√3)
=(19-12√3)/[4(-2+√3)]
=(19-12√3)(2+√3)/4
=(38-5√3-36)/4
=(2-5√3)/4