X-80%=25%x14x-0.8=3.5x=4.31/2X+30%X=4/5÷20%0.8x=4x=5(1-X):4=0.5:88(1-x)=21-x=1/4x=3/41/2+20%X=0.8750.5+0.2x=0.8750.2x=0.375x=1.8574/9X-12x85%=3/84/9x-51/5=3/84/9x=423/40x=3807/160