Answer
$f(t)=\dfrac{t+5}{(t+3)^2+4} $
Work Step by Step
We are given that $x=t-4$
Re-write as: $t=x+4$
When $a$ has a positive value then , shift the function to the right for $a$ units and when $a$ has a negative value then , shift the function to the left for $a$ units
Now, $f(t-4) =\dfrac{t+1}{(t-1)^2+4} $ and $f(x)=\dfrac{x+5}{(x+3)^2+4} $
So, we have the independent variable $t$ is: $f(t)=\dfrac{t+5}{(t+3)^2+4} $
