(10X+Y)-(10Y+X)=63 怎么解
问题描述:
(10X+Y)-(10Y+X)=63 怎么解
答
(10X+Y)-(10Y+X)=63
10x+y-10y-x=63
10x-x+y-10y=63
9x-9y=63
x-y=7