2X+60%X=7.8 x-405=300 70%x-50=260
2.6x=7.8 x=705 0.7x=310
x=3 x=73100
31x-25%x=1 120%-35%x=18.7 (2.6×80%-1.4×80%)÷20%
31x-0.25x=1 1.2-0.35x=18.7 =(2.6×0.8-1.4×0.8)÷0.2
121x=1 0.35x=19.9 = 1.2×0.8÷0.2
x=12 x=7398 =4.8
x+30%x=390
x+0.3x=390
1.3x=390
x=300