# What is the domain of f(x)=3x-1?

The domain for $f \left(x\right) = 3 x - 1$ is all real numbers.
The domain of a function is the set of input for a function, here $f \left(x\right)$, for which the function has a value. For any real numbers you plug into $x$, the function $f \left(x\right)$ will produce a value.
$f \left(0\right) = 3 \left(0\right) - 1 = 0$
$f \left(5\right) = 3 \left(5\right) - 1 = 14$
$f \left(71\right) = 3 \left(71\right) - 1 = 212$