已知l2x-4l+3l6+2yl=0,求下列各式的值 （1）lx+yl （2）lyl-lxl

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l2x-4l+3l6+2yl=0,
2x-4=0 6+2y=0
x=2 y=-3
|x+y|=|2-3|=1
|y|-|x|=3-2=1

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2x-4=0, 6+2y=0
x=2, y=-3
lx+yl =1 lyl-lxl=1

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