已知A=3x+2y^2,B=x^2-2x-y^2,若|x+2|+|y-√2|^2=0,求A-B的值.
问题描述：
已知A=3x+2y^2,B=x^2-2x-y^2,若|x+2|+|y-√2|^2=0,求A-B的值.
答
解∵/x+2/+/y-√2/²=0∴x+2=0,y-√2=0∴x=-2,y=√2A-B=(3x+2y²)-(x²-2x-y²)=3x+2x-x²+(2y²+y²)=-x²+5x+3y²=-(-2)²+5×(-2)+3×(√2)²=-4-10+6=-8