I believe it's B.
If I'm wrong tell me so I can see what I did wrong.
        
             
        
        
        
For a: 
you have your opposite side 
you need your hypotenuse 
you should use the s.o.h
        
             
        
        
        
All you have to do is combine like terms. 2c and (-c) are like terms (-5b) and (-b) are like terms and a is a term. So, 2c combined with (-c) is C. (-5b) and (-b) combined is (-6b). Since a doesnt need to be combined with anything, you leave it as it is so your answer will then be c - 6b + a (this is the answer assuming that there is a + in front of the a. If there is a - sign, then just change your +a to -a at the end
        
             
        
        
        
A) 100 degrees (congruent angle)
B) 45 degrees (congruent angle)
C) 90 degrees (right angle)
D) 99 degrees (congruent angle)
E) 30 degrees (congruent angle)
F) 30 degrees (180-150=30, that is to find the other angle that is congruent to f)
        
             
        
        
        
Answer:
Add 3 over each interval 
Step-by-step explanation: