x+1/5 = 6/5
(x+1)*5 = 30
5x + 5 = 30
5x = 25
x = 5
( x + 1 ) / x = 6 / 5 → produsul mezilor = produsul extremilor
⇒ 5 ( x + 1 ) = 6 x
6 x = 5 x + 5
6 x - 5 x = 5