If you put and label the three points in a line, you will see that RS + ST = RT.
Then you only need to substitue with the expressions given for RS and ST to find RT.
RT = x +1 + 2x - 2 = 3x - 1
Also, RT = 5x - 5
Then, 3x - 1 = 5x - 5
5x - 3x = 5 - 1
2x = 4
x = 4/2 = 2
X=2
