已知4x^2-y^2=20,2x+y=10,则2x-y=
已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知4x=9y求(1)x+y/y (2)y-x/2x
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
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/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
数学题已知p=x^/x-y-y^/x-y,q=(x+y)^-2Y(X+Y),
已知2x-y=10,求式子[(x^2+y^2)-(x-y)^2+2y(x-y)]/4y (4xy-2y²)/4
已知x+y=4,x^2+y^2=10,求(x-y)^2
已知x-2y/2x+3y=3/4,则x:y=
已知:x²y²-2x+6y+10=0则x+y=