Answer:
43°
Step-by-step explanation:
AD = (7x + 1)°
DC = 90° (right angle)
CB = (9x - 7)°
AD + DC = CB = AB
(7x + 1)° + 90° + (9x - 7)° = 180°
7x + 1 + 9x - 7 = 90
16x - 6 = 90
16x = 96
x = 96/16 = 6
AD = (7x + 1)° = (7*6 + 1)° = 43°
