若二次根式有意义,则x的取值范围是___________.
如果∠α与∠β是对顶角,∠α=30°,则∠β=_____.
(x+y)·(x+y)=.
(a-b)·(a-b)=;
a·a+a·a–a·a+a·a=.
x·x·xy=.