x+y=95 40%x+78%y=60%×65
问题描述：
x+y=95 40%x+78%y=60%×65
方程组
答
x+y=95
40x+78y=60*65
则
40x+78(95-x)=3900
40x-78x=3900-78*95
-38x=3900-7410=-3510
x=3510/38
y=95-3510/38能化成最简的吗就这样了。y=95-3510/38=[38*95-3510]/38=100/38