Question

Daca a supra b=2 supra 5,calculati 7a-2b supra 4a+3b

Answer 1

$\frac{a}{b} = \frac{2}{5}$⇒$\frac{a}{2} = \frac{b}{5}=k$

⇒a=2k
   b=5k
$\frac{7a-2b}{4a+3b} = \frac{7*2k-2*5k}{4*2k+3*5k} = \frac{14k-10k}{8k+15k} = \frac{4k}{23k} = \frac{4}{23}$