若x+y=7,xy=12,求(x+y)^2,x^2+y^2,(x-y)^2的值
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
如果x^2+xy+y-14,y^@+xy+x=28,求x+y的值.
若正数x,y满足x平方-y平方=2xy,求x-y除以x+y的值
若正数x,y满足x²-y²=2xy,求(x-y)/(x+y)的值
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方
4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/(x+2y-12Y²/x-2y)的值
若(y-x)/xy=3,求分式(2x+3xy-2y)/(x-2xy-y)的值
若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值
若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
x-y-x平方+2xy-y平方+2=0,求x-y的值
正整数x,y满足x2-y2=2xy,求x-y/x+y的值