[tex] \frac{3a+b}{5b-7a} [/tex]
Daca [tex] \frac{a}{3} = \frac{b}{4} [/tex] rezulta ca 4a=3b ⇒ a=3b-4 ,iar b=4a-3
Inlocuim:
[tex] \frac{3(3b-4)+b}{5b-7(3b-4)} [/tex]
[tex] \frac{9b-12+b}{5b-21b-4} = \frac{10b-12}{-16b-4}= \frac{2(5b-6)}{-4(4b+1)}= -\frac{5b-6}{2(4b+1)} [/tex]
