
William W. answered 01/20/22
Math and science made easy - learn from a retired engineer
For the numerator (x2 - 9) there are no restrictions on "x" so the domain of that portion is all real numbers.
For the denominator, there are two issues. 1) because of the √x, x must be a number zero or larger since square roots of negative numbers are not real. and 2) because dividing by zero is not defined, 2 - √x must not equal zero or x ≠ 4
So the domain is the set of all numbers greater than or equal to zero but less than 4 combined with numbers greater than 4.
You can write that as an inequality: 0≤x<4 U 4<x<∞ or in interval notation as [0, 4) U (4, ∞)
Maya C.
thank you!01/20/22