(1)已知(a+b)x2=9,(a-b)²=49,则a²+b²=?ab=?.
(2)已知a+b=6,a²+b²=10,求ab值.
人气:360 ℃ 时间:2019-10-31 13:49:52
解答
解(a+b)²=9这个吧即a²+2ab+b²=9①(a-b)²=49即a²-2ab+b²=49②①+②得:2a²+2b²=58∴a²+b²=29①-②得:4ab=-40∴ab=-10a+b=6(a+b)²=36即a²+2ab+b...
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