Determine the equation of the line that passes through the given points. (if you have a graphing calculator, you can use the table feature to confirm that the coordinates of both points satisfy your equation.) (3, 18) and (8, 33)

Finding such an equation is a fundamental skill in Algebra, and I urge you to become proficient in it.  

What I will do is find the slope of this line and then apply it in the point-slope formula for a straight line.
                     33-18
slope is m = = 15/5 = 3
                       8-3

Then the eqn of the line is y-18 = 3(x-3).

You could rewrite this equation in other formats if you so wished.

Iwould say they are complementary because that’s the division of a 90 degree angle and it’s split between the middle of them