13.√3ˣ * 5^(x/2) = 225
(3ˣ)^(1/2) * 5^(x/2) = 225
3^(x/2) * 5^(x/2) = 225
(3*5)^(x/2) = 225
15^(x/2) = 225
15^(x/2) = 15²
x/2 = 2
x = 2*2
x = 4
Ответ: 4