若x+y=3 ,x2-y2=24,则x-y=

若x+y=3 ,x2-y2=24,则x-y= 已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值 若x2-y2=6,x+y=3,则x-y= 若x-y=3,x2+y2=13/2,则x+y= x2+y2+x+y=18 x2+y2-2x-4x=24 解方程组 若x2+y2=4,则x-y最大值 x2+y2=4则4x+3y最大值 x+y=3,xy=-5,x2+y2=19,x2-xy+y2=24,求x-y 若f(x+y,x-y)=x2-y2,则f(x,y)=, 如题：若4x=5y(y≠0),则x2-y2/y2=?. 已知x,y满足（x2+y2）(x2+y2-1)=2,则x2+y2的值为多少?x2,y2表示x和y的平方 已知实数x,y满足3x2+2y2=6x,则x2+y2的最大值是 实数x、y满足3x2＋2y2=6x,则x2＋y2的最大值为 实数x,y满足x2/12+y2/4=1,则x2+y2-4x+3的最大值是_________________ 1.已知正数x,y满足x2-y2=2xy,求(x-y)/(x+y)的值2.若x2+xy-2y2=0则(x2+3xy-2y2)/x2-2y2)=_________3.先化简,后求值：(3-x)/(x-2)除以（x+2-2/(x-2)）,其中x=2√2  若|x-y|+（y+3）2=0,则x2+y2-2xy= x2+y2=208(x-y) 先化简,再求值:2x2-y2+2y2-3x2-2y2+x,其中x=-1,y=2