Start by remembering that the square root symbol gives the non-negative root. The equation says that √(x - 4) is 5. To remove the square root, square both sides: x - 4 = 5² = 25. Now isolate x by moving the constant to the other side, so x = 25 + 4 = 29. Always check radical equations: substituting x = 29 makes the expression inside the root equal to 25, and √25 = 5. So the correct answer is 29.