Here,
$\,x_1\,$ (read as ‘$\,x\,$ sub $\,1\,$’) denotes the $\,x$value of the first point,
and
$\,y_1\,$ (read as ‘$\,y\,$ sub $\,1\,$’) denotes the $\,y$value of the first point.
Similarly,
$\,x_2\,$ and $\,y_2\,$ denote the $\,x$value and $\,y$value of the second point.
Thus, to find the location that is exactly halfway between two points,
you average the xvalues, and average the yvalues.
The Midpoint Formula follows easily from the following observations:
$\displaystyle \cssId{s41}{(2,3)} \cssId{s42}{= \left(\frac{1+x}2,\frac{5+y}2\right)} $  use the Midpoint Formula 
$\displaystyle 2 = \frac{1+x}2\ $ and $\ \displaystyle 3 = \frac{5+y}2$ 
for ordered pairs to be equal, the first coordinates must be equal and the second coordinates must be equal 
$4 = 1 + x\ $ and $\ 6 = 5 + y$ 
clear fractions (multiply both sides of both equations by $\,2$) 
$5 = x\ $ and $\ 1 = y$  finish solving each equation 
$x = 5\ $ and $\ y = 1$  write your solutions in the conventional way 
CONCEPT QUESTIONS EXERCISE:
On this exercise, you will not key in your answer.However, you can check to see if your answer is correct. 
PROBLEM TYPES:
