若|x|=4,|y|=5,求|x+y|的算术平方根

若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若(x-y)(x+y)=5 ,(x+y)的二次方=4试求x-y 若（x-y）(X+y)=5,(x+y)平方=4,试求x-y的值 若(x-y)乘(x+y)=5,(x+y)^2=4,试求x-y的值 若x^2+y^2+5/4=2x+y,求x^Y+y^x的值? 已知5x-4y=0,求x:y和x+y:y的值 若x*x+4*y*y+2*x-4*y+2=0,求5*x*x+16*y*y的算术平方跟 若实数x、y满足x*x+y*y-2x+4y+5=0,求x-y的值 已知：4x = 5y,求(x+y) ：y 若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值 若x+y分之x-y=3,求式子x+y分之5(x-y)—2(x-y)分之x+y的值 若x-y分之x+y=3,求式子x+y分之5(x-y)—2（x-y）分之x+y的值 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 若x-y=1,求代数式x(x-y)+y(y-x)+2013的值 若x*x+y*y=x+y-1/2,求x,y的值如题 若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若x的平方-y的平方=15,x+y=5,求x-y