已知x-2y=3,2x^2-8y^2=5,则x+2y=

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已知x-2y=3,2x^2-8y^2=5,则x+2y=
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已知x-2y=3,2x^2-8y^2=5,则x+2y=
已知x-2y=3,2x^2-8y^2=5,则x+2y=

已知x-2y=3,2x^2-8y^2=5,则x+2y=
2x²-8y²
=2(x+2y)(x-2y)=5
所以x+2y=5/[2(x-2y)=5/6

2x^2-8y^2=2(x^2-4y^2)=2(x-2y)(x+2y)=5

x-2y=3

6(x+2y)=5
x+2y=5\6

2x^2-8y^2=5
2(x^2-4y^2)=5
(x+2y)(x-2y)=5/2
(x+2y)=(5/2)/(x-2y)=(5/20)/3=5/6

2(x∧2-4y∧2)=2(x-2y)(x+2y)=5,2×3×(x+2y)=5,
x+2y=5/6