The numerical length of TU is 5
Here, we want to get the value of TU
Since T is on SU, we have the length of SU calculated as;
[tex]\begin{gathered} SU\text{ = ST + TU} \\ 8\text{ = 3x + 4x+1} \\ 8\text{ = 7x + 1} \\ 8-1\text{ = 7x} \\ 7\text{ = 7x} \\ x\text{ = }\frac{7}{7} \\ x\text{ = 1} \\ TU\text{ = 4x + 1 } \\ TU\text{ = 4(1) + 1 = 4+1 = 5} \end{gathered}[/tex]