方程组1.{x+y+1=0,x^2+4y^2=8 2.{(x-3)^2+y^2=9,x+2y=0 3.{x+y=6,xy

方程组1.{x+y+1=0,x^2+4y^2=8 2.{(x-3)^2+y^2=9,x+2y=0 3.{x+y=6,xy 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 解方程组 x^2+2xy+y^2=9,(x-y)^2-4(x-y)+3=0 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组, 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} 求方程组的解,方程组xy/(2x+y)-xy/(2x-y)=3,xy/(2x-y)+xy/(2x+y)=4 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* 已知x.x+y.y+8x+6y+25=0,求代数式(x.x-4y.y)/(x.x+4xy+4y.y)-x/(x+2y)的 解方程组：2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16 ｛x-y+xy=1,3x-y=4｝和｛x/2+y/2=2y,y=2x/3｝哪个是二元一次方程组? 3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组 解方程组 x-y/3-x+y/4=2 x-y/6-x+y/8=3