Answer: SU = 4(1) + 1 = 5
Explanation:
Since T is on segment SU we know the whole is eqaul to the sum of it’s parts.
ST + TU = SU substitute
3x - 1 + 3x = 4x + 1 simplify
6x - 1 = 4x + 1 solve for x
2x = 2
x = 1
ST = 3(1) -1 = 2
TU = 3(1) = 3
SU = 4(1) + 1 = 5