Question - Determine Variable Types

For (a) \( x^2 - 5 \): This is a polynomial expression, and it contains a variable \( x \) which can take any real number value.

For (b) \( \frac{1}{m^2} \): This expression also contains a variable \( m \), which denotes a non-zero real number since \( m \) cannot be equal to zero to avoid division by zero.