已知实数x,y满足3^x+5^y>3^(-x)+5^(-y),则下列式子成立的是( )A.x+y＞0 B.x+y＜0 C.x-y＞0 D.x-y＞0

已知实数x,y满足约束条件x+y>3,y 已知实数x,y满足2x+5y>=10;2x-3y>-6;2x+y 已知实数x,y满足x-y 已知实数X,Y满足{|x+y| 已知实数x,y满足y=x^2+5x-4,则3x-2y最大值为 已知实数x,y满足：y 已知实数x,y满足3x+4y=5,则根号x^2+y^2的最小值等于 已知实数x,y满足3x+4y=5,则根号x^2+y^2的最小值等于 已知实数xy满足|x|/4+|y|/3 已知实数x,y,满足x-√x-1=√y+3-y,则x+y最大值是? 已知实数x,y满足（x+y)(x+y+3)-4=0则x+y的值是 已知实数x,y满足x=√(9-x+2y)+√(3x-6y-27)+5,则-2x-y的立方根为 已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y 已知变量x,y满足约束条件：x+y≧1,y≦3,x-y≦1,若z=Kx+y最大值为5,则实数k 已知实数x,y满足|x+y+7|+(xy-5)^2=0,求3x^2y^3+3x^3y^2 已知实数x,y满足√2x+y-5+(3x-2y+3)²=0,求3x-2/3y 已知实数x,y满足根号3x-5y+1+|x-3y+3|=0,求3/2x-y/2的值 设实数x,y满足3