已知(a-b)^2=7,(a=b)^2=13,求a^2+b^2和ab的值

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已知(a-b)^2=7,(a=b)^2=13,求a^2+b^2和ab的值已知(a-b)^2=7,(a=b)^2=13,求a^2+b^2和ab的值已知(a-b)^2=7,(a=b)^2=13,求a^2+

已知(a-b)^2=7,(a=b)^2=13,求a^2+b^2和ab的值
已知(a-b)^2=7,(a=b)^2=13,求a^2+b^2和ab的值

已知(a-b)^2=7,(a=b)^2=13,求a^2+b^2和ab的值
a^2-2ab+b^2=7
a^2+2ab+b^2=13
2(a^2+b^2)=20
a^2+b^2=10
4ab=6
ab=3/2

(a=b)^2=13, ?是(a+b)^2=13吧?
a^2+b^2=10 ab=3/2

(a-b)^2+,(a+b)^2=2a^2+2b^2=20
a^2+b^2=10
(a-b)^2-,(a+b)^2=--4ab=--6
ab=2/3