Răspuns :
[tex] \frac{a}{6} [/tex] = [tex] \frac{2}{3} [/tex] ⇒ a ·3=2·6 3a=12 ⇒a= 12:3 = 4
[tex] \frac{a}{6} = \frac{2}{3} => a= \frac{6x2}{3} = \frac{12}{3} => a=4[/tex]