若x,y>0,1/2(x+y)=4则xy的最大值为

若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 若|x-3|+（y+2）=0,则（x-y+4xy/x-y）（x+y-4xy/x+y）的值是 若|x-3|+（y+2）²=0,则（x-y+4xy/x-y）（x+y-4xy/x+y）的值是 若x+y=1,x不等于0则x+(2xy+y^2)/x/(x+y)/x= 若(2x-14xy-2y)除以(x-2xy-y)=4,则1/x-1/y= 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若|X+Y-4|+(XY-1)^2=0,则X^2+Y^2=__________ 若x,y>0,1/2(x+y)=4则xy的最大值为 若x²-4xy+5y²-2y+1=0,求x,y 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( ） 若（x+1)^2+|y-2|=0,求3x^2-[5xy-(x^2y-3xy)+4x^2y-8xy]的值 若2x^2-6xy+9y^2-4x+4=0,则y/x-x/y=若2x^2-6xy+9y^2-4x+4=0,则y/x-x/y=? 若3x-2y=0,则4x/x²-xy+y²=? 若|x-2|+x²+1/4y²-xy=0 x= y= 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 若实数x,y满足x^2-xy-y^2 =0,则x/y=? 已知x+y=1,x>0,y>0,则2x+y/xy等于