4. Реши уравнения.

а) x/26 = 5/13 → x = 26 * 5 / 13 = 10. б) 15y / 9 = 2.16 / 4.8 → y = 2.16 * 9 / (4.8 * 15) = 0.27. в) 92 / 23 = 128 / (17 + a) → 4 = 128 / (17 + a) → 4(17+a) = 128 → a = 15. г) 3.5 / 0.25 = (5^3) / b → 14 = 125/b → b = 125/14 ≈ 8.93.