rs=3x , rt=6x-3 and st=3x.
We are given point s is between r and t points.
So, the end points are r and t.
Because s is between r and t, the sum of rs and st equals rt.
Weo, we can setup an equation as,
rs + st = rt.
Plugging values of rs , st and rt in above equation.
3x + 3x = 6x - 3.
Adding 3x+3x, we get 6x.
6x = 6x - 3
Subtracting 6x from both sides, we get
6x-6x = 6x-6x - 3 .
0=-3.
But that is not possible.
So, we could say, rs + st = rt could not be possible for given values of rs, st and rt, that is rs=3x , rt=6x-3 and st=3x.