Question

Решите, пожалуйста срочно

Answer 1

$left (frac{2x}{2x+y} - frac{4x^2}{4x^2+4xy+y^2} right ):left ( frac{2x}{4x^2-y^2} + frac{1}{y-2x} right )=\\=left ( frac{2x}{2x+y} - frac{4x^2}{(2x+y)^2} right ):left ( frac{2x}{(2x-y)(2x+y)} - frac{1}{2x-y} right )=\\= frac{2x(2x+y)-4x^2}{(2x+y)^2} : frac{2x-(2x+y)}{(2x-y)(2x+y)} = frac{2xy}{(2x+y)^2} cdot frac{(2x-y)(2x+y)}{-y} =\\= -frac{2x(2x-y)}{2x+y} = frac{2x(y-2x)}{2x+y}$

$2)quad sqrt{(2-sqrt5)^2} + sqrt{(3-sqrt5)^2} =|2-sqrt5|+|3-sqrt5|=\\=-(2-sqrt5)+(3-sqrt5)=-2+sqrt5+3-sqrt5=-2+3=1\\P.S.; ; ; sqrt5approx 2,24 textgreater 2; ; Rightarrow ; ; 2-sqrt5 textless 0; ; Rightarrow ; ; |2-sqrt5|=-(2-sqrt5)$