Răspuns :
[tex] \frac{a + b}{a - b} = 3 \\ \frac{a + b}{2} = 9 \\ a + b = 18 \\ \frac{18}{a - b} = 3 \\ 3(a - b) = 18 \\ a - b = 6 \\ a = b + 6 \\ a + b = b + 6 + b = 18 \\ 2b + 6 = 18 \\ 2b = 12 \\ b = 6 \\ a = 12[/tex]
[tex] \frac{a + b}{a - b} = 3 \\ \frac{a + b}{2} = 9 \\ a + b = 18 \\ \frac{18}{a - b} = 3 \\ 3(a - b) = 18 \\ a - b = 6 \\ a = b + 6 \\ a + b = b + 6 + b = 18 \\ 2b + 6 = 18 \\ 2b = 12 \\ b = 6 \\ a = 12[/tex]