4x2+12xy+9y2=1 x2+2xy+y2-4=0 4x2-9y2=0 x2-2xy+y2-1=0(解方程组）

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+4y2+x2y2+1=6xy,则(x4-y4)/(2x2+xy-y2)*(2x-y)/(xy-y2)/(x2+y2/y)2= 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） 4x2+12xy+9y2=1 x2+2xy+y2-4=0 4x2-9y2=0 x2-2xy+y2-1=0(解方程组） x2-2xy+y2=4 x2+y2-x-y=6 解不等式x2-2xy+y2=4 x2+y2-x-y=6 解不等式 已知x(x-1)-(x2-y)=-2求x2+y2-4xy的值 4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy 解方程组 x2+2xy+y2-4=0 x2-2xy+y2-1=0 已知x2+y2+4x-2y+5=0,求x2+2xy+y2值 因式分解：x2－9a2＋12a－4；x2y+3xy2-x-3y；1-x2-2xy-y2；3a2+2b-2ab-3a；x2+y2+2xy+ax+ay；3x4-48y48a3-4a2-2a+1；x2-3xy-28y2；(x2-x)^2-4(x2-x)-12 x2+y2+2xy=256 x2+y2-2xy=4 (x2, 2x2+xy-3y2+x+4y-1因式分解 1.（x+1）（x+2）-x-102.（x2-2x（x2-2x-4）+43.x2-3xy-18y2-3x-9y2.(x2-2x）（x2-2x-4）+4 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x/y+y/x=2,求(x2+xy+y2)/(x2-4xy+y2)的值 ( x2+xy+y2) ( x2+xy+2y2)-12y4 (x2-2xy+y2)-(x2+2xy+y2)=什么 (x2+xy+y2)-4xy(x2+y2)