We have the expression:

When we have rational functions, where the denominator is a function of x, we have a restriction for the domain for any value of x that makes the denominator equal to 0.
That is because if the denominator is 0, then we have a function f(x) that is a division by zero and is undefined.
If we have a value that makes f(x) to be undefined, then this value of x does not belong to the domain of f(x).
Expression:

Answer: There is no restriction for x in the expression.
20%, because 20/100 is equal to 20&.
Hope this helps!
The factors are just numbers that can be multiplied to receive the number that is given.
The factors of 24 are: 1, 2, 3, 4, 6, 8, 12, 24.
1 × 24 = 24
2 × 12 = 24
3 × 8 = 24
4 × 6 = 24