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If 2x+3y=8 and x y=2 , find the value of...

If `2x+3y=8` and `x y=2` , find the value of `4x^2+9y^2`

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Given
`2x+3y=8`
squaring both sides
we get,
`4x^2+9y^2+12xy=64`
`4x^2+9y^2+12(2)=64`
`4x^2+9y^2+24=64`
`4x^2+9y^2=64-24`
so
`4x^2+9y^2=40`
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