a+b=15.6,a-b=2.8,求ab值

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a+b=15.6,a-b=2.8,求ab值a+b=15.6,a-b=2.8,求ab值a+b=15.6,a-b=2.8,求ab值a+b=15.6,a-b=2.8a=9.2,b=6.4(a+b)^2=24

a+b=15.6,a-b=2.8,求ab值
a+b=15.6,a-b=2.8,求ab值

a+b=15.6,a-b=2.8,求ab值
a+b=15.6,a-b=2.8
a=9.2,b=6.4

(a+b)^2=243.36
(a-b)^2=7.84
4ab=(a+b)^2-(a-b)^2=235.52
ab=235.52/4=58.88

a+b=15.6,
a-b=2.8
解得:b=6.4
a=9.2
a*b=58.88

(a+b)²-(a-b)²=4ab
=15.6²-2.8²
=(15.6+2.8)(15.6-2.8)=18.4x12.8
∴ab=18.4x12.8÷4
=58.88