已知(a+b)²=6,(a-b)²=30,则a²+b²= ,ab=?,
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![已知(a+b)²=6,(a-b)²=30,则a²+b²= ,ab=?,](/uploads/image/z/3676494-30-4.jpg?t=%E5%B7%B2%E7%9F%A5%28a%2Bb%29%26%23178%3B%3D6%2C%28a-b%29%26%23178%3B%3D30%2C%E5%88%99a%26%23178%3B%2Bb%26%23178%3B%3D+%2Cab%3D%3F%2C)
已知(a+b)²=6,(a-b)²=30,则a²+b²= ,ab=?,
已知(a+b)²=6,(a-b)²=30,则a²+b²= ,ab=?,
已知(a+b)²=6,(a-b)²=30,则a²+b²= ,ab=?,
(a+b)²=6,(a-b)²=30
则a²+b²+2ab=6,a²+b²-2ab=30
a²+b²=(30+6)÷2=18
ab=(6-30)÷2÷2=-6