[tex]\it b)\ \ \ 25\%=\dfrac{\ \ 25^{(25}}{100}=\dfrac{1}{4}\\ \\ \\ \dfrac{x}{y}=\dfrac{1}{4}\Big|_{\cdot2} \Rightarrow \dfrac{2x}{y}=\dfrac{2}{4} \Rightarrow \dfrac{2x+y}{y}=\dfrac{2+4}{4} \Rightarrow \dfrac{2x+y}{y}=\dfrac{^{25)}6}{\ \ 4}=\dfrac{150}{100}=150\%[/tex]
[tex]\it c)\ \ \dfrac{x}{y}=\dfrac{1}{4} \Rightarrow \Big(\dfrac{x}{y}\Big)^2=\Big(\dfrac{1}{4}\Big)^2 \Rightarrow \dfrac{x^2}{y^2}=\dfrac{1^2}{4^2} \Rightarrow \dfrac{x^2}{y^2}=\dfrac{1}{16}[/tex]
