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

学习 时间:2026-04-07 19:50:12 阅读:9742
若(3xy+2)+|7-x-y|=0,求代数式(5xy+10y)-[-5x-(4xy-2y+3x)]的值.

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缓慢的大雁

忐忑的星星

2026-04-07 19:50:12

(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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  • 傻傻的电脑
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    2026-04-07 19:50:12

    (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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