[tex]\it E(x) = \left(\dfrac{(x+2)^2}{x^2+4}-1 \right):\dfrac{x}{x^2+4}= \left(\dfrac{x^2+4x+4}{x^2+4}-1 \right)\cdot\dfrac{x^2+4}{x}= [/tex]
[tex]=\it \dfrac{x^2+4x+4}{x^2+4}\cdot \dfrac{x^2+4}{x} -\dfrac{x^2+4}{x} =\dfrac{x^2+4x+4}{x} - \dfrac{x^2+4}{x} = [/tex]
[tex]\it \dfrac{x^2+4x+4 -x^2-4}{x} = \dfrac{4x}{x} = 4[/tex]
