2x2-3xy-2y2=0 x2+y2=5

若X2+xy-2y2=0,则（x2+3xy+y2)/x2+y2=? (x2-2xy+y2)-(x2+2xy+y2)=什么 解方程组 x2 -2xy -y2 =1 2x2 -5xy -3y2 =0 x2+3xy+2y2=0,则x2+y2/xy x2-3y2=2xy过程 2x2-3xy-2y2=0 x2+y2=5 x2+y2=10 3x2+2xy-y2=0 解二元二次方程组 已知x2+xy=3,xy+y2=-2,则2x2-xy-3y2= 已知x2-3xy=-5,xy+y2=3,求x2-2xy+y2. 如果x2+y2=5,那么代数式(3x2-2xy-y2)-(x2-2xy-3y2)的值为 解方程组 ｛3x2-y2=8 {4x2+12xy+9y2=1 {x2+2xy+y2-4=0 x2+xy+y2=4 4x2-9y2=0 x2-2xy+y2-1=0还有{x2+y2=4xy-y2+4=0x2-----x的平方 y2------y的平方 还有{2x-3y=12x2-3xy+y2-4x+3y-3=0 已知(x2+y2+3)(x2+y2-2)-6=0,求x2+y2的值 解方程组 x2+2xy+y2-4=0 x2-2xy+y2-1=0 已知X2次方+XY=3,XY+Y2次方=-2,求下例值:X2次方-Y2次方 若x不等于0是x2+xy-2y2=0,则x2+3xy+y2/x2+y2=急!详细!10分钟哦! 解方程组 x2 -2xy -y2 =1 2x2 -5xy -3y2 =0解方程组 x2 -2xy -y2 =12x2 -5xy -3y2 =0 x2+y2+2xy=256 x2+y2-2xy=4 (x2, 解一元二次方程组 x2-2xy+y2=1 2x2-5xy-3y2=0补充结果