(1+30%)*90%X+(1+20%)*90%X(200-X)90%=200+27.7
1.3×0.9x+1.2×0.9x（200-x）×0.9=227.7
1.17x+1.18x（180-0.9x）=227.7
1.17x+212.4x-0.9x=227.7
212.67x=227.7
x=21267/22770
解方程每一步我都要哦!(1+30%)*90%X+(1+20%)*90%X(200-X)90%=200+27.7
(1+30%)*90%X+(1+20%)*90%X(200-X)90%=200+27.7
1.3×0.9x+1.2×0.9x（200-x）×0.9=227.7
1.17x+1.18x（180-0.9x）=227.7
1.17x+212.4x-0.9x=227.7
212.67x=227.7
x=21267/22770