We are given the function rule:

$f(x) = 5x - 1 + x^2$

Step 1: Substitute $x = 12$

$f(12) = 5(12) - 1 + 12^2$

Step 2: Compute Each Term

$5(12) = 60$

$12^2 = 144$

$60 - 1 + 144 = 203$

Final Answer:

$f(12) = 203$

Would you like a more detailed explanation?

Here are some related questions to practice:

1. Find $f(15)$ using the same function rule.
2. What is $f(0)$?
3. How does this function behave as $x$ increases?
4. What type of function is this (linear, quadratic, or something else)?
5. Can you rewrite this function in standard quadratic form?

Tip: Always follow the order of operations (PEMDAS) when evaluating functions.