Misconception: √x always has two answers (positive and negative)
While the equation x² = 4 has two solutions (x=2 and x=-2), the radical symbol '√' denotes the principal root, which is the non-negative one. Therefore, √4 is defined as 2, not ±2. If both answers are needed, the notation ±√4 is used.
Misconception: Distributing roots over addition/subtraction
You cannot distribute a root over addition or subtraction. This is a common algebraic error. For example, √(a² + b²) is NOT equal to a + b. Take √(9 + 16) = √25 = 5. This is not the same as √9 + √16 = 3 + 4 = 7.