已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值 帮帮已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值

已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值 帮帮已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值
已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值 帮帮
已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值

已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值 帮帮已知x²+y²=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y²的值
答案15

5x²-3xy-5y²-11xy-8x²＋ymd9,intent:#Intent;S.K_1171477665=;end

解
5x²-3xy-5y²-11xy-8x²+2y²
=(5x²-8x²)+(-3xy-11xy)+(2y²-5y²)
=-3x²-3y²-14xy
=-3(x²+y²)-14xy
=-3×9-14×(-3)
=42-27
...

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解
5x²-3xy-5y²-11xy-8x²+2y²
=(5x²-8x²)+(-3xy-11xy)+(2y²-5y²)
=-3x²-3y²-14xy
=-3(x²+y²)-14xy
=-3×9-14×(-3)
=42-27
=15

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