已知xy=-2,x+y=3求代数式(3xy+10y)+[5x-(2xy+2y-3x)]的值

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已知xy=-2,x+y=3求代数式(3xy+10y)+[5x-(2xy+2y-3x)]的值

已知xy=-2,x+y=3求代数式(3xy+10y)+[5x-(2xy+2y-3x)]的值
已知xy=-2,x+y=3求代数式(3xy+10y)+[5x-(2xy+2y-3x)]的值

已知xy=-2,x+y=3求代数式(3xy+10y)+[5x-(2xy+2y-3x)]的值
(3xy+10y)+[5x-(2xy+2y-3x)]
=3xy+10y+5x-2xy-2y+3x
=3xy-2xy+10y-2y+5x+3x
=(3xy-2xy)+(10y-2y)+(5x+3x)
=xy+8y+8x
=xy+8*(x+y)
=-2+8*3
=-2+24
=22

(3xy+10y)+[5x-(2xy+2y-3x)]
=3xy+10y+[5x-2xy-2y+3x]
=3xy+10y+5x-2xy-2y+3x
=xy+8x+8y
=xy+8(x+y)
=-2+8*3
=-2+24
=22

(3xy+10y)+[5x-(2xy+2y-3x)]
=-6+10y+[5x-(-4+2y-3x)]
=-6+10y+5x+4-2y+3x
=-6+4+8x+8y
=-2+8(x+y)
=-2+8*3
=-2+24
=22