In this equation, you have to treat the number in the bracket first on the basis of BODMAS
15 - [-3]- 4
Note that when two minuses come together the product is a plus sign.
15 +3 - 4
You have to add before you subract
18 - 4 =14
Therefore, 15- [-3] - 4 = 14.
        
             
        
        
        
The formula to find the measure of an interior angle is 

, where 

 represents the number of sides in the polygon. In this problem, 

 would represent 

. 
Let's plug in the value for 


Let's simplify that. 

Now we know that the <span>measure of an interior angle of a regular three-sided polygon is 60</span>°. 
Your answer would be B!Let me know if you have any questions regarding this problem!
Thanks!
-TetraFish
 
        
        
        
The answer is -4 i just did the test
 
        
             
        
        
        
Answer:
There are no values of x that makes the equation true. or in other words ( no solution)