# What is f(a+2) if f(x)=3x+5/x?

$f \left(a + 2\right) = 3 \left(a + 2\right) + \frac{5}{a + 2}$
Given a defined function $f \left(x\right)$, we can evaluate the function at any constant by replacing every $x$ with that constant.
So if $f \left(x\right) = 3 x + \frac{5}{x}$, then $f \left(a + 2\right) = 3 \left(a + 2\right) + \frac{5}{a + 2}$