已知全集U=﹛2,2a,a²-4﹜,集合A=﹛2,a²-3﹜,CuA=﹛5﹜,则a=___
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![已知全集U=﹛2,2a,a²-4﹜,集合A=﹛2,a²-3﹜,CuA=﹛5﹜,则a=___](/uploads/image/z/5437971-27-1.jpg?t=%E5%B7%B2%E7%9F%A5%E5%85%A8%E9%9B%86U%3D%EF%B9%9B2%2C2a%2Ca%26%23178%3B-4%EF%B9%9C%2C%E9%9B%86%E5%90%88A%3D%EF%B9%9B2%2Ca%26%23178%3B-3%EF%B9%9C%2CCuA%3D%EF%B9%9B5%EF%B9%9C%2C%E5%88%99a%3D___)
已知全集U=﹛2,2a,a²-4﹜,集合A=﹛2,a²-3﹜,CuA=﹛5﹜,则a=___
已知全集U=﹛2,2a,a²-4﹜,集合A=﹛2,a²-3﹜,CuA=﹛5﹜,则a=___
已知全集U=﹛2,2a,a²-4﹜,集合A=﹛2,a²-3﹜,CuA=﹛5﹜,则a=___
2a=a²-3;
a²-2a-3=0;
(a-3)(a+1)=0;
a=3或a=-1;
a²-4=5;
a=±3;
∴a=3;
2a=5;
a=5/2;
a²-4=a²-3;
无解;
∴a=3;