(⁵√3)ˣ + (¹⁰√3)ˣ⁻¹⁰ = 84
(¹⁰√3)²ˣ + (¹⁰√3)ˣ/(¹⁰√3)¹⁰ = 84
(¹⁰√3)ˣ = t > 0
t² + t/3 = 84
3t² + t - 252 = 0
D = 1 + 4*3*252 = 3025 = 55²
t12 = (-1 +- 55)/6 = - 28/3 9
t = -28/3 нет < 0
t = 9
(¹⁰√3)ˣ = t
(¹⁰√3)ˣ = 9
3^x/10 = 3^2
x/10 = 2
x = 20
