Отметь правильные свойства, если:

1.√a ⋅ a = a^2

2. √a - √b = √a-b

3. √a ÷ √b = √a ÷ b

4. √a^2 = a, a ≥ 0

5. √a ⋅ a = a, a ≥ 0