已知|x²-2xy-8y²|+2√x²-4xy+4y²-1=0,求3x+6y的值.
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![已知|x²-2xy-8y²|+2√x²-4xy+4y²-1=0,求3x+6y的值.](/uploads/image/z/2095657-25-7.jpg?t=%E5%B7%B2%E7%9F%A5%7Cx%26%23178%3B-2xy-8y%26%23178%3B%7C%2B2%E2%88%9Ax%26%23178%3B-4xy%2B4y%26%23178%3B-1%3D0%2C%E6%B1%823x%2B6y%E7%9A%84%E5%80%BC.)
已知|x²-2xy-8y²|+2√x²-4xy+4y²-1=0,求3x+6y的值.
已知|x²-2xy-8y²|+2√x²-4xy+4y²-1=0,求3x+6y的值.
已知|x²-2xy-8y²|+2√x²-4xy+4y²-1=0,求3x+6y的值.
即x²-2xy-8y²=0
x²-4xy+4y²-1=0
(x-4y)(x+2y)=0
且(x-2y)²=1
若x-4y=0
x=4y
则(4y-2y)²=1
y=±1/2
3x+6y=3*4y+6y=18y=±9
若x+2y=0
则原式=3(x+2y)=0
综上
原式=-9或9或0