I would appreciate _________ you could work with us to communicate to the American people ________ there are no more funds available for further improvement of social security.
A:it that, if
B:that, if
C:it if, that
D:if, that
- Finish your homework ________ you can't play games.
- All right, Mum.
如图,在正方形ABCD的外侧,作等边△ADE,则∠AEB=____.
当A、B两点中有一点在原点时,不妨设点A在原点,
如图1,|AB|=|OB|=|b|=|a﹣b|;
当A、B两点都不在原点时,
如图2,点A、B都在原点的右边
|AB|=|OB|﹣|OA|=|b|﹣|a|=b﹣a=|a﹣b|;
如图3,点A、B都在原点的左边,
|AB|=|OB|﹣|OA|=|b|﹣|a|=﹣b﹣(﹣a)=|a﹣b|;
如图4,点A、B在原点的两边,
|AB|=|OB|+|OA|=|a|+|b|=a+(﹣b)=|a﹣b|;
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