What should be the value of x in equation ( x / sqrt(216) ) = ( sqrt(96) / x )

Question

Sqrt(x+1)-sqrt(x-1) = sqrt(4x-1) , we get the solution after solving as x=5/4 . But when we subsitute x=5/4 back in the equation we get 1=2 . Why ??

Answer 1

x^2 = (96 × 216)^(0.5)
x^4 = 96 × 216.
x = 12.