A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=a,y=-3,且-2A=2a,求A值
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![A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=a,y=-3,且-2A=2a,求A值](/uploads/image/z/1333379-11-9.jpg?t=A%3D2x%26%23178%3B-3xy%2By%26%23178%3B-x%2B2y%2CB%3D4x%26%23178%3B-6xy%2B2y%26%23178%3B%2B3x-y%2C%E8%8B%A5x%3Da%2Cy%3D-3%2C%E4%B8%94-2A%3D2a%2C%E6%B1%82A%E5%80%BC)
A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=a,y=-3,且-2A=2a,求A值
A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=a,y=-3,且-2A=2a,求A值
A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=a,y=-3,且-2A=2a,求A值
是不是-2A+B=2a
所以-4x²+6xy-2y²+2x-4y+4x²-6xy+2y²+3x-y
=5x-5y
=5a+15=2a
a=-3
A=18-27+9+3-6=-3
A=2a²+9a-a-6
-2A=2a=-4a²-9a+2a+12
a=2a²-3.5a+6
少了条件