Question

Given Trinagle ABC with A(-4, -2), B(4,4), and C(18,-8), answer the following questions.

Answer 1

For the answer to the question above, the slope of segment AC is  (-6/22) = -3/11.

The slopes of perpendicular lines are negative reciprocals, so 
you know that the slope of the perpendicular bisector will be 11/3.

The midpoint of segment AC is  (7, -5).

Now you have the slope of the perpendicular bisector, and a
point on it.  You should be able to complete the equation now.

Notice how sneaky this question is.  You don't need to know
point-B at all, and you don't even need to know that there's
any triangle.  All you need to know is points  A  and  C.