已知(x+y)^2=7,(x-y)^2=13,求(1)x^2+y^2 (2)xy
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知xy=2,x-y=3,求(x+y)(x-y)-y^2-(6x^2y-2xy^2)/2y的值.
已知xy=-2,x-y=3,求(x+y)(x-y)-y平方+(x-y)平方-(6x2y-2xy平方)/2y的值
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+xy-2y^2=0 (x不等于0,y不等于0),求x/y-y/x-(x^2+y^2)/xy的值
初中数学分式已知x/y=2,求(x*x-xy+3y*y)/x*x+xy+6y*y的值
已知(x+2)^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy
已知:13x^2-6xy+y^2-4x+1=0,求(x+y)^2013*x^2011
已知x^2+y^2-4x+6y+13=0求(xy+y^2/5x^2-5xy+xy+y^2)·(5/x+y)-(y/x-y
已知,x+y=2,xy=-1,求下列代数式的值:x(x+y)(x-y)-x(x+y)的平方
已知x+y=1,xy=-2分之1,利用因式分解求:x(x+y)(x-y)-x(x+y)²的值
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²