given f(x)=2x^2 - 9, what is the value of f(5)?

To find the value of \( f(5) \) for the function \( f(x) = 2x^2 - 9 \), we plug in \( x = 5 \):

\[ f(5) = 2(5)^2 - 9 \]

Calculating \( (5)^2 \):

\[ (5)^2 = 25 \]

Now substituting this back into the equation:

\[ f(5) = 2(25) - 9 \]

Calculating \( 2(25) \):

\[ 2(25) = 50 \]

Now, subtracting 9:

\[ f(5) = 50 - 9 = 41 \]

Thus, the value of \( f(5) \) is \( \boxed{41} \).