若(3xy+2)+|7-x-y|=0,求代数式(5xy+10y)-[-5x-(4xy-2y+3x)]的值.

学习 时间:2026-05-30 12:36:25 阅读:6932
若(3xy+2)+|7-x-y|=0,求代数式(5xy+10y)-[-5x-(4xy-2y+3x)]的值.

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义气的白昼

机智的秋天

2026-05-30 12:36:25

(3xy+2)^2+|7-x-y|=0,则 3xy+2=0,7-x-y=0,即 x+y=7,xy= -2/3 (5xy+10y)-[-5x-(4xy-2y+3x)] =5xy+10y-(-5x-4xy+2y-3x) =5xy+10y+5x+4xy-2y+3x =9xy+8x+8y =9xy+8(x+y) = 9*(-2/3)+8*7 = -6+56 = 50

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  • 懵懂的狗
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    2026-05-30 12:36:25

    (3xy+2)^2+|7-x-y|=0,则 3xy+2=0,7-x-y=0,即 x+y=7,xy= -2/3 (5xy+10y)-[-5x-(4xy-2y+3x)] =5xy+10y-(-5x-4xy+2y-3x) =5xy+10y+5x+4xy-2y+3x =9xy+8x+8y =9xy+8(x+y) = 9*(-2/3)+8*7 = -6+56 = 50

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