x²+y²=100,xy=48,问x=?y=?
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
X²+2xy+y²/xy乘x²-2xy+y²/xy+y²=
x²+xy/(x-4y)(x+y),其中x=4,y=-1
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
x/y=3,求x²+y²-xy/x²-y²的值.
2x+y=0,求4x²+2xy(x+y)+y³
(x+3y)(x-y)-(x+y)^2 =x²-xy+3xy-3y²-x²-y²
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知x+y=4.x-y=6.求代数式xy(y²+y)-y²(xy+2x)-3xy的值
已经z1=x+y+(x^2-xy-2y)i,z2=(2x-y)-(y-xy)i,问x,y取什么时候实数值时
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(