Let y = √{(5 + x)*(5 - x)}

=> y = √(5 - x² )

=> y² = 5 - x²

=> x² = 5 - y²

=> x = √(5 - y² )

Now, √(5 - y² ) is defined, when

      5 - y² ≥ 0

=>  y² - 5 ≤ 0

=> y² - (√5)² ≤ 0

=> (y - √5)*(y + √5) ≤ 0

=> -√5 ≤ y ≤ √5

Since, the square root of a number is always non-negative.

So, the range of √{(5 + x)*(5 - x)} is 0 ≤ y ≤ √5