She is ________ careful as me, but I'm ________ than you.
A:as; much careful
B:as; much more careful
C:so; more careful
D:so; very careful
图形(1)是以点____为中心旋转的;图形(2)是以点____为中心旋转的;图形(3)是以点____为中心旋转的。
已知(x+y)2=18,(x﹣y)2=6,求x2+y2及xy的值