x+y=42 0.8%x+1.1%y=42*1%「解方程组
问题描述：
x+y=42 0.8%x+1.1%y=42*1%「解方程组
答
x+y=42 => y=42-x
0.8%x+1.1%y=42*1% => 8x+11y=420
=> 8x+11(42-x)=420
=> (11-8)x=(11-10)*42
=> 3x=42
=> x=14
=> y=42-x=28
∴x=14,y=28