Answer:
g(x) = 3x +5
Explanation:
You want the function that results from translating f(x) = 3x upward by 5 units.
Translation
The y-coordinate of a point tells how far above the x-axis it is. Adding 5 to the y-coordinate will move that point 5 units farther above the x-axis, which is to say 5 units upward.
The y-coordinate of a point on a graph is the value of the function of the x-coordinate of that point. That is, each point is (x, f(x)). If we want to translate that point 5 units upward, we add 5 to the function value:
(x, f(x) +5) . . . . . graph translated 5 units up
Using the given definition of f(x), this becomes ...
(x, 3x +5)
The translated function is defined as g(x), so we have ...
(x, g(x)) = (x, 3x +5)
or ...
g(x) = 3x +5