To evaluate the function [tex]\( f(x) = 5x^2 \)[/tex] at [tex]\( x = 3 \)[/tex], follow these steps:
1. Substitute [tex]\( x = 3 \)[/tex] into the function:
[tex]\[
f(3) = 5 (3)^2
\][/tex]
2. Calculate the square of 3:
[tex]\[
3^2 = 9
\][/tex]
3. Multiply the result by 5:
[tex]\[
5 \times 9 = 45
\][/tex]
So, the value of the function [tex]\( f(x) \)[/tex] when [tex]\( x = 3 \)[/tex] is 45.
Therefore, the correct answer is:
[tex]\[ \boxed{45} \][/tex]
