What is the clearest way to indicate various operations along the following lines:
$f(x) = 3x$: The function $f$ multiplies its input by 3.
$g(x) = x-5$: The function $g$ decreases its input by 5.
$h(x) = 2^x$: The function $h$...Raises 2 to the power of its input? Exponentiates its input on a base of 2? Takes 2 to its input?
In the first two cases, I made a choice of whether to refer to the operation's name ("multiply") or a (hopefully) plain language action being performed ("decrease"). For the function $f$, I could have said that it triples its input or increases its input by 200%, but these don't seem to generalize well for the purposes of communicating, and the latter is almost never obvious to students. Similarly, I could have said that the function $g$ subtracts 5 from its input, but I am not convinced this is any simpler than "decreases its input by".
Is there a simplest verb phrase for exponents? What do you think is clearest for students if I want to maintain the form "The function $h$ ____________"?