Answer:
31 degrees 
Step-by-step explanation:
well each three point of a triangle equals 180
so 20+35= 55   180-55= 125 
now if the exterior angle is 156 and it should equal 180 the interior angle would be 24 degrees 
now we have 24 and 125 so angle ? = 31
 
        
             
        
        
        
20/2-10/5. You divide 20 by 2 and subtract that from 10 divided by 5
        
             
        
        
        
Answer:
The equivalent expressions are;
9x + 9
and 
9(x + 1) 
Step-by-step explanation:
Mathematically, we should understand that an equilateral triangle has all of its sides equal 
So if one side is 3x+ 3, the other sides too measures same 
Therefore, the length of the rope represents the perimeter of the triangle 
This is obtainable by adding all the side lengths together 
This will be;
3x + 3 + 3x + 3 + 3x + 3 = 9x + 9
This is also same as 9(x + 1)