x/12.5+(50-x)/5=7两边同时乘以25得2x+5(50-x)=1752x+250-5x=175-3x=175-250-3x=-75x=25
x/12.5+(50-x)/5=7乘以25得2x+5(50-x)=1752x+250-5x=175-3x=-75x=25
50*(x/12.5)+10*(50-x)=3504x+500-10x=350-6x=-150x=25