已知x²-y²=8,x-y=2,求(1)xy (2)(x+y)² (3)x²+y
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
2x²-3xy=y²=0(x,y不得o)求x/y+y/x
已知实数x,y满足x²+y²-xy+2x-y+1=0 求x y
已知x-3y=0,y≠0,求x²-2xy+y²分之2x+y×(x-y)的值
已知2x+y=0,求x-2y/x²+xy*(x²-y²)/x²-4xy+4y
已知,x-y=5,xy=6,求(x+y)²-2x-2y+1的值
已知(x+3)+丨X-y+10丨=0 ,求5x²y-[2x²y-(3xy-xy²)-3x&
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
已知x-3y=0,求(x²-2xy+y²/x-y)-2y的值
已知X²+3XY-4Y²=0(Y≠0)求X-Y/X+Y
已知x/y=3,求x²+2xy-3y²/x²-xy+y²