Respuesta :

[tex]\begin{gathered} 3=\frac{1}{2}x+\frac{1}{4}x=\frac{2}{4}x+\frac{1}{4}x=\frac{3}{4}x,\text{ therefore} \\ \frac{3}{4}x=3\rightarrow x=3\cdot\frac{4}{3}=4 \end{gathered}[/tex]