一 ?
— I'm looking for a hat for myself.
A:What are you doing
B:What can I do for you
C:What did you say
已知x﹣y=3,则代数式(x+1)2﹣2x+y(y﹣2x)的值是____
一个多边形的每个内角都是144°,则它的边数是( )