Answer:
ABC=17
Step-by-step explanation:
so angle abd is 87°. than the equation look like this.
angle abc+ cbd =angle abd
9x -1°+6x+58°=87°
15x+57°=87°
15x=87° - 57°
15x=30°
30/15=x
x=2
angle abc=9x-1°
and 9x-1° equal to 9×2-1 = 18 - 1 = 17
