Question 1402
 Solve sqrt(5x+1) +2 = 2x
 sqrt(5x+1) = 2x - 2,
 Squaring both sides: 5x + 1 = 4(x-1)^2 = 4x^2 -8x +4.
 Or  4x^2 - 13x + 3 =0,
 Factoring: (x-3)(4x -1) = 0,
 So,x = 3 or 1/4

 Check, when x =3, sqrt(5*3+1) +2 = sqrt(16) + 2 = 4+2 = 6
                   = 2*3 =6  (right)
  when x =1/4, sqrt(5/4+1) +2 = sqrt(9/4) + 2 = 3/2 + 2 = 7/2
               = 2 * 1/4 - 2 = -3/2 (invalid, ignore, it is
   the redundant root obtained by taking square)

 Answer: The only roor is x= 3.