Answer:
TU = 12 units
Explanation:
Given that T is a point on line segment SU.
So that;
SU = ST + TU
But, SU = 3x - 7, TU = x - 1, and ST = x + 7.Thus,
SU = ST + TU
3x - 7 = (x + 7) + (x - 1)
3x - 7 = x + 7 + x - 1
3x - 7 = 2x + 6
Collecting like terms.
3x - 2x = 6 + 7
x = 13
Therefore,
TU = x - 1
= 13 - 1
= 12
TU = 12 units
ST = x + 7
= 13 + 7
= 20 units
SU = 20 + 12
= 32 units