【急啊!】已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?会追加的!~~~~~~~~~~~~~~~~~~~~a²+2a-3=5 是怎么得来的呢?最后一消,就剩下a²+2a-3
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![【急啊!】已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?会追加的!~~~~~~~~~~~~~~~~~~~~a²+2a-3=5 是怎么得来的呢?最后一消,就剩下a²+2a-3](/uploads/image/z/6893573-5-3.jpg?t=%E3%80%90%E6%80%A5%E5%95%8A%21%E3%80%91%E5%B7%B2%E7%9F%A5%E5%85%A8%E9%9B%86U%3D%7B2%2C3%2Ca%26sup2%3B%2B2a-3%7D%2CA%3D%7B%7Ca%2B7%7C%2C2%7D%2CCuA%3D%7B5%7D%2C%E6%B1%82a%E7%9A%84%E5%80%BC%3F%E5%B7%B2%E7%9F%A5%E5%85%A8%E9%9B%86U%3D%7B2%2C3%2Ca%26sup2%3B%2B2a-3%7D%2CA%3D%7B%7Ca%2B7%7C%2C2%7D%2CCuA%3D%7B5%7D%2C%E6%B1%82a%E7%9A%84%E5%80%BC%3F%E4%BC%9A%E8%BF%BD%E5%8A%A0%E7%9A%84%21%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7E%7Ea%26sup2%3B%2B2a-3%3D5+%E6%98%AF%E6%80%8E%E4%B9%88%E5%BE%97%E6%9D%A5%E7%9A%84%E5%91%A2%EF%BC%9F%E6%9C%80%E5%90%8E%E4%B8%80%E6%B6%88%EF%BC%8C%E5%B0%B1%E5%89%A9%E4%B8%8Ba%26sup2%3B%2B2a-3)
【急啊!】已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?会追加的!~~~~~~~~~~~~~~~~~~~~a²+2a-3=5 是怎么得来的呢?最后一消,就剩下a²+2a-3
【急啊!】已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?
已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?
会追加的!~~~~~~~~~~~~~~~~~~~~
a²+2a-3=5 是怎么得来的呢?
最后一消,就剩下a²+2a-3了,怎么还=5???怎么得的???【急啊!】
但是2,3已经是5了啊
a²+2a-3应该是0了啊
【急啊!】已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?已知全集U={2,3,a²+2a-3},A={|a+7|,2},CuA={5},求a的值?会追加的!~~~~~~~~~~~~~~~~~~~~a²+2a-3=5 是怎么得来的呢?最后一消,就剩下a²+2a-3
a²+2a-3=5 所以a=2或a=-4
检验:当a=2,A={9,2},U={2,3,5}(不符,舍去)
当a=-4,A={3,2},U={2,3,5}(符合)
综上所述:a=-4
a²+2a-3=5,|a+7|=3,联立为方程组,解得 a=-4
-4
由题意可知:|a+7|=3 a=-4或-10
a²+2a-3=5 a=2或-4
所以
a=-4
a=-4
1.a²+2a-3=5解得a=-4或a=2
2.|a+7|=3解得a=-4或a=-10
综上a=-4