(x+1)^2+y^2+4-4y=0,则x+y=

已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? |x-2y+1|+(x+y-5)²=0,则5x+4y= 常微分方程的通解dy/dx=(x-y+1)/(x+y-3)y^4=2y^n+y=0y''+6y'+9y=e^(-3x)y''+y'-2y=4e^(2x) 如果|x-y+1|+y^2-4y+4=0,求出x,y的值 实数X.Y满足X*X+Y*Y-2X-2Y+1=0,则（Y-4）/（X-2）的取值范围是? 若实数X,Y满足X²+Y²+4X-2Y +1=0,则X²-6X+Y²-2Y的最大值是多少 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） (x+1)^2+y^2+4-4y=0,则x+y= x*x+2x+y*y-4y+5=0 x= y= {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 {4x-3y-10=0 3x-2y=0,{3x-4(x-y)=2 2x-3y=1,{2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 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*y)的值 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 设实数x,y 满足x²+4y²+2x-4y+2+0 则x+y= x^2+y^2-2x+4y-20=0则y/x的最大值,x+y的最大值 如果有理数x.y满足x^2+y^2+4x-6y+13=0,则y^x=?