你好，题目不完整。设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y 若|x-2a|+(y+3)²=0,且B-2A=a,求A的值由|x-2a|+(y+3)²=0得：x=2a，y=-3，B-A=(4x²-6xy+2y²+3x-y)-2(2x²-3xy+y²-x+2y)=5X-5Y∴10a+15=a9a=-15a=-5/3.
