Given the equation square root of 2x plus 1 = 3, solve for x and identify if it is an extraneous solution.

To answer the question above, raise both sides of the equation to the power of two. 
                                (sqrt (2x + 1))² = 3²
This will simplify into,
                                     2x + 1 = 9
Solving for the value of x gives an answer of x = 4. This value is not an extraneous root as it satisfy the original equation even if it is inside the radical sign.