plzzz help ! if you could do a step by step ill mark brainliest

Answer:
m∠ABU = 70°
Step-by-step explanation:
By applying angle addition postulate,
m∠ABC = m∠UBC + m∠ABU
145° = 75° + m∠ABU
m∠ABU = 145° - 75°
m∠ABU = 70°
Therefore, measure of angle ABU is 70°.