1.﹙2又5/9+2又5/9+2又5/9﹚×0.25=(2又5/9)*3*1/4=69/36=23/12 2.1/8X﹙X+0.5﹚＝75％ 1/8x*x+1/16x-3/4=0 2x*x+x-12=0 x=(-1±√97)/4
