To solve the equation √(4x+5) = 12, we need to isolate the variable x.

First, let's square both sides of the equation to eliminate the square root:

(√(4x+5))^2 = 12^2

4x + 5 = 144

Next, subtract 5 from both sides of the equation:

4x = 144 - 5

4x = 139

Finally, divide both sides of the equation by 4 to solve for x:

x = 139/4

Therefore, the solution to the equation √(4x+5) = 12 is x = 139/4.