Răspuns:
[tex] \bf \frac{2x}{12} = \frac{4}{5} \\ \\ \bf 2x \cdot 5 = 12 \cdot 4 \\ \\ \bf 2x \cdot 5 = 48 \\ \\ \bf 2x = 48 \div 5 \\ \\ \bf 2x = 9.6 \\ \\ \bf x = 9.6 \div 2 \Rightarrow \red{ \boxed{ \bf x = 4.8} } [/tex]
