Yesterday, I visited a middle school in Taiyuan. There are about students in it.
A:two thousand
B:two thousands
C:two thousands of
D:two thousand of
用“☆”定义一种新运算:对于任意有理数a和b,规定a☆b=ab2+2ab+a.
如:1☆3=1×32+2×1×3+1=16.
(1)求(﹣2)☆3的值;
(2)若(a+12☆3)☆(﹣12)=8,求a的值;
(3)若2☆x=m,(14x)☆3=n(其中x为有理数),试比较m,n的大小.
我国面积最大的沙漠是____沙漠;该地区由风力作用形成____地貌。