They are complementary because if you were to put them on top of one another they'd line up. (same degree measurement)
The value of f(19) in the given equation is 55.
<h3>What is the function of a linear equation?</h3>
The function of a linear equation illustrates a straight line graph and for a given set of input into the function, there is usually a specific output.
Given that:
We are to find the f(x) = 19.
So;
f(19) = 3(19) - 2
f(19) = 57 - 2
f(19) = 55
Learn more about the function of a linear equation here:
brainly.com/question/14323743
#SPJ1