Question

stiind ca 4a+b/3a-b=4, aflati a/b

Answer 1

$\frac{a}{b} =k$   ⇒  a=kb

$\frac{4a+b}{3a-b} = \frac{4kb+b}{3kb-b} = \frac{b(4k+1)}{b(3k-1)} =4$

⇒4k+1=4(3k-1)  ⇒   4k+1=12k-4   |scad 4k din ambii membrii ai egalitatii ⇒4k-4k+1=12k-4k-4  ⇒1=8k-4   | adun 4  ⇒1+4=8k+4-4  ⇒5=8k  ⇒k=$\frac{5}{8}$