Final answer:
The value of the function g(r) at r = 3 is -2.
Step-by-step explanation:
To evaluate the function g(r) = -5r + 13 at r = 3, we substitute 3 for r in the function:
g(3) = -5(3) + 13
g(3) = -15 + 13
g(3) = -2
Therefore, the value of the function g(r) at r = 3 is -2.