x>0,y>0,x+y=1,求8/x+2/y的最小值?

已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) 已知X*X+Y*Y+6X-8Y+25=0 求（Y/X)+(X/Y)-2=? x*x+2x-y*y+6y-8=0,x+y不等于2,求x-y的值 设x>0,y>0,x+y=1,求8/x+2/y的最小值 x>0,y>0,x+y=1,求8/x+2/y的最小值? x^+2x+1+y^2-8y+16=0求y/x 已知x求^2+y^2-6x-8y+25=0求1/x-y /x+y/x^4-y^4 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x²+y²+6x-8x+25=0,求（x/x²-y² - 1/x+y）÷y/y-x 若(x+y)(x+y-1)-2=0,求x+y的值求 求导数y=3x-x^2 求y',y'/ x=1 y'/x=0 x-2y+3=0 求x^2-(4y+1)x+4y^2+8y 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)的值 求y=(x^2)+2x(x≥0) y=-x+2x(x 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^2-8x+y^2-y+16又1/4=0,求[(x+y)(x-y)-(x+y)^2-2y(x-3y)]÷4y的值