Explicație pas cu pas:
[tex] \frac{x}{12} = \frac{ (\frac{1}{3} + \frac{1}{4} )}{7} \\ \\ \frac{x}{12} = \frac{ \frac{4}{12} + \frac{3}{12} }{7} \\ \\ \frac{x}{12} = \frac{ \frac{7}{12} }{7} \\ \\ \frac{x}{12} = \frac{7}{12} \div 7 \\ \\ \frac{x}{12} = \frac{7}{12} \times \frac{1}{7} \\ \\ \frac{x}{12} = \frac{1}{12} \\ \\ = > x = 1[/tex]
Sper că te-am ajutat!