Let f(x) = x2 + 3x + 2. Find the equation of the line containing (1, f(1)) and (3, f(3)).

Answer 1

(1,f(1)) = (1,6)
(3,f(3)) = (3,20)

If you are in Calculus, you just have to know at this stage how to find the equation of a line given two points.