Question 970326
Midpoint is half of the x values (the mean or average of the two) and half the y-values.

x values are -9 and 8.  Add them (-1).  Take half of it (-1/2)

y values are -2 and 6.   Add them (4).  Take half (2)

The midpoint is (-1/2,2)

{{{graph(300,300,-9,8,-10,10,(8x/17)+(38/17))}}}

The line shown has the x-values at the end.  The midpoint will be (-1/2.2)