#### Answer

6, -1, 1, -6

#### Work Step by Step

As established in questions 26 and 27, R can be 5 or -5, and T can be 7 or -7. This makes 4 options for lines.
R=5, T=7
R=5, T=-7
R=-5, T=7
R=-5, T=-7
To find the midpoint of these lines, take the average of the two points (to do this, add them up and divide by two). This gives 6, -1, 1, and -6.