x>0 y>0 x+y=1 证(x+1/x)(y+1/y)≥25/4

若|x+2y-1|+y²+4y+4=0,求（2x-y）²-2（2x-y)(x+2y)+(x+2y)& x,y属于R*,且x+y=1,求证:(1)(x+1/x)(y+1/y)≥25/4 (2)(x+1/x)^2+(y+1/y x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y 设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于 1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [（x+y)(x-y)-(x-y)^2+2y(x-y 1、x(x-y)(x+y)-x(x+y)^2 以下三个行列式的计算过程是什么.谢谢 1.x y x+y y x+y x x+y x y 2.1 x y z x 1 0 实数x,y满足{x-y+1>=0;y+1>=0;x+y+1 x>0 y>0 x+y=1,4/X+9/y最小值 {3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1 ｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1