已知实数a,b满足a平方+3a-1=0,b平方-3b-1=0,且ab≠1,求a负2次方+3b的值
问题描述:
已知实数a,b满足a平方+3a-1=0,b平方-3b-1=0,且ab≠1,求a负2次方+3b的值
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答
有a^2+3a-1=0解得a = (-3 ± √13)/2同理b = (3±√13)/2那么有四种可能了(1)a = (-3+√13)/2 b = (3+√13)/2(2)a = (-3 - √13)/2 b = (3+√13)/2(3)a = (-3+√13)/2 b=(3-√13)/2(4)a=(-3-√13)/2 b = (3-√13)/2...