Look at the axis graph. If both of the coordinates are negative, it would be in quadrant lll. If you go over to the x-axis, you would be in quadrant lV, or 4.
(-2,-3) -> (2,-3)
You change the x-factor's sign. 
I hope this helps!
~kaikers
 
        
             
        
        
        
Answer:
(b) the unknown angle is 80°
Step-by-step explanation:
The unkown angle is:
[2(x-10)]°
Substituting "x" by 50 (part a)
[2(50-10)]°=[2(40)]°=80°
 
        
             
        
        
        
The answer would be D just took test