Question

Exercitiul 2, va multumesc.

Answer 1

a/b=3/5
=> 5a=3b => b=5a/3

Acum inlocuiesti b-ul in cea de a doua ecuatie

3a+b = 28 => 3a+ 5a/3 = 28(acum aduci la acelasi numitor)

=> 9a + 5a = 84
14a =84
a=6 => b= 5*6/3=10

Answer 2

2. 

a / b = 3 / 5 

a / 3 = b / 5 = K 

a / 3 = K => a = 3 K
b / 5 = K => b = 5 K

⇒ 3 · 3 K + 5 K  = 28

9 K + 5 K = 28

14 K = 28 

K = 28 : 14 

K = 2 

a = 2 · 3 = 6 

b = 2 · 5 = 10