notez a/b=k (/ fractie) ⇒a=bk
[tex] \frac{5a+2b}{7a-2b} = \frac{1}{2}
[/tex]
⇒[tex] \frac{5*bk+2b}{7*bk-2b} = \frac{b(5k+2)}{b(7k-2)}= \frac{(5k+2)}{(7k-2)}= \frac{1}{2}
[/tex]
[tex]\frac{(5k+2)}{(7k-2)}= \frac{1}{2}
[/tex] ⇒ 2(5k+2)=7k-2
10k+4=7k-2 k= -2/1 =a/b
