x+30%x=26
x+0.3x=26
1.3 x=26
x=26/1.3
x=2040%x-30=2640%x-30=260.4x-30=260.4x=30+26=56 x=56/0.4=560/4x=140(1-25%)x=15(1-25%)x=15(1-0.25)x=150.75x=15 x=15/0.75=1500/75 x=202x+20%x=3.32x+20%x=3.32x+1.2x=3.33.2x=3.3x=3.3/3.2=33/32x=1又1/32