有一道题“先化简,再求值:(
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+
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)÷
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,其中x=-
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.”小丽做题时把“x=-
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”错抄成了“x=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101190200669350402/SYS201311011902006693504015_ST/5.png)
”,但她的计算结果也是正确的,请你解释这是怎么回事?
考点分析:
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已知:如图,等腰梯形ABCD中,AD∥BC,BD平分∠ABC,∠A=120°,BD=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101190200669350402/SYS201311011902006693504014_ST/0.png)
.
(1)求证:AB=AD;
(2)求△BCD的面积.
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化简:(-2x)
2+(6x
3-12x
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如图:六边形ABCDEF中,AB平行且等于ED,AF平行且等于CD,BC平行且等于FE,对角线FD⊥BD.已知FD=4cm,BD=3cm.则六边形ABCDEF的面积是
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2.
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在下面等式的□内填数,○内填运算符号,使等式成立(两个算式中的运算符号不能相同):□○□=-6.
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