Answer:
I got the same question on Khan Academy. I was going to ask that too but saw that you already did. Maybe try to point it out to someone else on Brainly. Sorry that I could not help.
Step-by-step explanation:
Answer:
C) 8
Step-by-step explanation:
-5(a+3)=-55
a+3=-55/-5
a+3=11
a=11-3
a=8
Angles 8 and 15 are supplementary.