2013^2-2011*2015
=2013^2-(2013-2)*(2013+2)
=2013^2-(2013^2-4)
=2013^2-2013^2+4
=4
猜你喜欢
- 1形容逐渐变化的词语
- 21L1mol \L的碳酸钠溶液吸收S02的量大于1Lmol/L硫化钠溶液吸收SO2的量
- 3-How long has the film been on?-___3:30.A.At B.About C.Before D.Since
- 4Here is a letter for you.（挑错）
- 5初中知识物理外电路断开时的路端电压和没断开时是一样的不?
- 6there is no doubt that modern technology has affected our language.____ can be seen
- 7请问,杠杆动力,阻力的方向如何确定?
- 8求以椭圆八分之x平方+五分之y平方=1的焦点为顶点,而以椭圆的顶点为焦点的双曲线方程
- 9英语15.Shortly after the accident,two ________ police were sent to the spot to keep order.
- 101.一项工程,甲单独完成要56小时,乙单独完成要80小时,现在甲乙工程合作,需多少小时完成?