设A=2x²-3xy+y²+x-3y,B=4x²-6xy+2y²+4x-y,若|x-3a|+(y+3)²=0,且B-2A=a,求A的值.
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![设A=2x²-3xy+y²+x-3y,B=4x²-6xy+2y²+4x-y,若|x-3a|+(y+3)²=0,且B-2A=a,求A的值.](/uploads/image/z/1995870-30-0.jpg?t=%E8%AE%BEA%3D2x%26%23178%3B-3xy%2By%26%23178%3B%2Bx-3y%2CB%3D4x%26%23178%3B-6xy%2B2y%26%23178%3B%2B4x-y%2C%E8%8B%A5%7Cx-3a%7C%2B%EF%BC%88y%2B3%EF%BC%89%26%23178%3B%3D0%2C%E4%B8%94B-2A%3Da%2C%E6%B1%82A%E7%9A%84%E5%80%BC.)
设A=2x²-3xy+y²+x-3y,B=4x²-6xy+2y²+4x-y,若|x-3a|+(y+3)²=0,且B-2A=a,求A的值.
设A=2x²-3xy+y²+x-3y,B=4x²-6xy+2y²+4x-y,若|x-3a|+(y+3)²=0,且B-2A=a,求A的值.
设A=2x²-3xy+y²+x-3y,B=4x²-6xy+2y²+4x-y,若|x-3a|+(y+3)²=0,且B-2A=a,求A的值.
|x-3a|+(y+3)²=0,
|x-3a|=0,(y+3)²=0,
x=3a,y=-3
B-2A=a
4x²-6xy+2y²+4x-y-2(2x²-3xy+y²+x-3y)=a
4x²-6xy+2y²+4x-y-4x²+6xy-2y²-2x+6y=a
2x+5y=a,因x=3a,y=-3
6a-15=a
a=3
x=9,y=-3
A=2x²-3xy+y²+x-3y=2*81+81+9+9+9=270