Start by remembering that the square root symbol gives the non-negative root. The equation says that √(x + 1) is 2. To remove the square root, square both sides: x + 1 = 2² = 4. Now isolate x by moving the constant to the other side, so x = 4 - 1 = 3. Always check radical equations: substituting x = 3 makes the expression inside the root equal to 4, and √4 = 2. So the correct answer is 3.