4x+y-1=0 2y-2x+1=0 求二元一次方程的解

x^2-x+y^2+2y+5/4=0 求x^-1+y^0 3x+4y-5=0 x^2+y^2=1求x.y x>0 Y>0x+y=2求1/x+4/y的最小值 已知x求^2+y^2-6x-8y+25=0求1/x-y /x+y/x^4-y^4 x²-4x-1=0,求(2x-3)²-(x+y)(x-y)-y² 若(x+y)(x+y-1)-2=0,求x+y的值求 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 求导数y=3x-x^2 求y',y'/ x=1 y'/x=0 已知:x-2y+3=0 求x^2-(4y+1)x+4y^2+2y x-2y+3=0 求x^2-(4y+1)x+4y^2+8y 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) 已知实数x、y满足|2x-y+1|+3根号3x-2y+4=0,求代数式[(x-y)/(x-2y)]/(x的平方-2y)/[(x的平方-y的平方）/x的已知实数x、y满足|2x-y+1|+3根号3x-2y+4=0,求代数式[(x-y)/(x-2y)]/(x的平方-2y)/[(x的平方-y的平方）/（x的 已知(3x+1)(3x-3)-3x+2)^2=-7,(y+7)(y-7)-y(y-7)=0,求8y^2-5y(-y+3x)+4y(-4y-5/2x)的值 已知(2x+1)*2+y*2+2y+1=0 求{(x*2+y*2)-(x-y)*2+2y(x-y)}/(2y) 已知4y^2+4y+1+|x-1|=0 求[(x-2y)^2-(2x+y)(2x-y)+(3x-y)(x+y)]÷（2y）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