c)
[tex]\it \dfrac{x+2}{x}=0,25 \Rightarrow \dfrac{x+2}{x}=\dfrac{\ \ 25^{(25}}{100} \Rightarrow \dfrac{x+2}{x} = \dfrac{1}{4} \stackrel{derivare}{\Longrightarrow}\ \dfrac{x+2-x}{x} =\dfrac{1-4}{4} \\ \\ \Rightarrow \dfrac{2}{x}=\dfrac{-3}{4} \Rightarrow x = \dfrac{2\cdot4}{-3} \Rightarrow x = -\dfrac{8}{3}[/tex]
e)
[tex]\it \dfrac{^{2)}11,5}{2,5}=\dfrac{x+4,5}{x-4,5} \Rightarrow \dfrac{23}{5}=\dfrac{x+4,5}{x-4,5} \stackrel{derivare}{\Longrightarrow} \ \dfrac{23-5}{5} =\dfrac{x+4,5-x+4,5}{x-4,5}\\ \\ \Rightarrow \dfrac{18}{5}=\dfrac{9}{x-4,5} \stackrel{derivare}{\Longrightarrow}\ \dfrac{\ 18^{(9}}{9}=\dfrac{5}{x-4,5} \Rightarrow \dfrac{2}1} = \dfrac{5}{x-4,5} \Rightarrow \\ \\ \Rightarrow2\cdot(x-4,5)=1\cdot5 \Rightarrow 2x-9=5\Rightarrow2x=14\Rightarrow x=7[/tex]
