已知xy满足x2/9+y2/16=1(1)求x2-8x+y2的范围 (2)(y-2)/(x-4)的范围

已知xy满足x2/9+y2/16=1(1)求x2-8x+y2的范围 (2)(y-2)/(x-4)的范围 已知实数xy满足x2+y2=3,若m=y+1/x+3 已知两个实数xy,满足x2+y2=1,求x+根号3y最大值 已知x,y满足x2/9+y2/4=1,则xy的取值范围是? 已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值 已知x2+4y2+x2y2+1=6xy,则(x4-y4)/(2x2+xy-y2)*(2x-y)/(xy-y2)/(x2+y2/y)2= 已知实数x,y满足1≤x2+y2≤4,求f(x,y)=x2+xy+y2的最大值和最小值 已知实数x.y满足（x2+y2）（x2+y2-1）=2,求x2+y2的值 已知实数XY 满足X2+Y2=1,求Y+2/X+1的取值范围 已知实数x、y满足X2+y2-xy+2x-y+1=0,试求x、y的值 已知实数x,y满足(x2)+(y2)-xy+2x-y+1=0,求x,y的值 已知实数x、y满足X2+y2-xy+2x-y+1=0,试求x、y的值 已知实数xy满足x2+y2=4.则y+3/x+1的取值范围为 已知实数xy满足x2+y2=4.则y+3/x+1的取值范围为 已知A=5x2次方+2xy-4y2次方,B=-x2次方-4xy+y2次方,C=x2次方-xy+3y2次方,其中xy满足其中xy满足|2x+1|+（y-4）2次方=0,求A-2B+C的值 已知x2+xy=5,xy+y2=-1,则x2-y2=( )今天就要用的, 已知y/x=1/2,求(x2+2xy+y2)/﹙x2-xy-2y2)的值. 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