Answer:
Step-by-step explanation:
∠WTX = ∠WUV (facing same arc WV)
9x + 18 = 15x
6x = 18
x = 3
In ΔXUV,
∠VXU = 180 - 15x - (3x + 21)
= 180 - 18x - 21
= 159 - 18(3)
= 159 - 54
= 105°