(0.2x+0.5)/0.5-(0.03+0.02x)/0.03=(x-5)/2
(2x+5)/5-(3+2x)/3=(x-5)/2
乘以30得 6(2x+5)-10(3+2x)=15(x-5)
12x+30-30-20x=15x-75
12x-20x-15x=-75
-23x=-75
x=75/23