已知x+y=xy=4,求x²+y²,x^4+y^4,x^8+y^8的值
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知非零有理数x,y满足x²-4xy+4y²=0,求x-y/x+y-y-x/x+y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的平方+y的平方-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
已知:x/y=4/5,求y²/(x²-xy+y²)的值
已知x+y=xy=4,求x²+y²,x^4+y^4,x^8+y^8的值
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²的值
已知x+4y-2x+8y+5=0,求x^4-y^4/2x+xy-y·2x-y/xy-y÷(x+y/y)的值.
已知x²+4y²-6x+8y+13=0,求x-y/x+y的值.
已知x.x+y.y+8x+6y+25=0,求代数式(x.x-4y.y)/(x.x+4xy+4y.y)-x/(x+2y)的
已知:(x+y)²=4,(x-y)²=6,求x²+y²和xy的值.