That is an exponential function. It grows all over the range, from - ∞ to + ∞.
The limit when f(x) goes of - ∞ is zero, so y = 0 there is the asymptote to the left side.
The value of f(x) for x = 4 is 1: f(4) = 6 ^ (4 - x) = 6 ^ (4 - 4) = 6^0 = 1. So, the y intercept is y = 0.
The function grows as x goes to infinity.
You can finds some other values of the function to help to sketch the graph.
x f(x) = 6 ^ (x - 4)
-100 6^ ( -104) = 1.18 * 10^ (-81)
- 10 6^ (-14) = 1.28 - 10^ -11
3 6^ (-1) = 1/6 = 0.17
4 6^0 = 1
14 6^ (10) = 60,466,176
