Answer:
TU = 18
Step-by-step explanation:
TV = 21
TU + VU = 21
-31 - 7z + (-39 - 6z) = 21
-31 - 7z - 39 - 6z = 21
-7z - 6z - 31 - 39 = 21 {Combine like terms}
-13z - 70 = 21 {Add 70 to both sides}
-13z = 21 + 70
-13z = 91 {divide both side by (-13)}
z = 91/-13
z = -7
TU = -31 - 7z
= -31 - 7*(-7)
= - 31 + 49
= 18
