x+35 x+35-20 x+35 x+35-20
问题描述：
x+35 x+35-20 x+35 x+35-20
答
x+35=50
x+35-20=50-(20 )
x+35 x+35-20 x+35 x+35-20
x+35=50
x+35-20=50-(20 )