# If f(x) = 3x + 1, then what is f(3)?

Jan 16, 2017

$f \left(3\right) = 10$

#### Explanation:

To calculate $f \left(3\right)$ we need to substitute $\textcolor{red}{3}$ for $\textcolor{red}{x}$ in the function:

$f \left(\textcolor{red}{x}\right) = 3 \textcolor{red}{x} + 1$ becomes:

$f \left(\textcolor{red}{3}\right) = \left(3 \times \textcolor{red}{3}\right) + 1$

$f \left(\textcolor{red}{3}\right) = 9 + 1$

$f \left(\textcolor{red}{3}\right) = 10$