1. **Problem statement:** Find $f(3)$ given $f(x) = 5x + 2$. 2. **Formula used:** To find $f(3)$, substitute $x = 3$ into the function $f(x)$. 3. **Calculation:** $$f(3) = 5(3) + 2$$ $$= 15 + 2$$ $$= 17$$ 4. **Explanation:** We replaced $x$ with 3 in the expression for $f(x)$ and simplified the arithmetic to get the value of the function at 3. **Final answer:** $$f(3) = 17$$