3a / 2b = 5 / 3⇒3×3a=5×2b⇔9a=10b⇒a=10b/95a + 2b = 204 in loc de a aici vom scroe 10b/9 pt ca asa ne-a dar a mai sus5×10b/9+2b=204
50b/9+2b=204 aduc la acelasi numitor
50b/9+9×2b/9=204
50b/9+18b/9=205
68b/9=204⇒b=204×9/60⇒b=1836/68⇒b=27
daca b=27 si 5a+2b=204⇒5a+2×27=204
5a+54=204
5a=204-54
5a=150
a=150/5
a=30
daca a=30 si b=27⇒a-b=30-27=3