6sin(pi/6x)=5

x = 5/3π

If you meant:

6sin(π /(6x))=5 , 0 ≤ x ≤ 2π
sin(π /(6x))=5/6
π /(6x) = .98511 or π /6x = π - .98511 = 2.15648
x = .5315 or x = .2428

if you meant:
6sin((π /6)x)=5 , 0 ≤ x ≤ 2π
π/6 x = .9851 or π/6 x = 2.15648
x = 1.88142 or x = 4.1186

the robot's answer of 5/3π or even 5/(3π) is incorrect , as expected