Factors of 9: 1; 3; 9
Factors of 36: 1; 2; 3; 4; 6; 9; 12; 18; 36
GCF(9; 36) = 9
        
             
        
        
        
3x-12 = 12x
-12 = 9x
-12/9 = x
x= -4/3
        
                    
             
        
        
        
Answer:
x = 15
Step-by-step explanation:
The two angles form a straight line so they add to 180 degrees
3+6x   + 5x+12 = 180
Combine like terms
11x+15 = 180
Subtract 15 from each side
11x+15-15 =180-15
11x = 165
Divide by 11
11x/11 =165/11
x =15
  
        
             
        
        
        
To round money to the nearest cent you would see in the ones place what that number is and if it is at or higher than 5 it would round up to 2.20               
Did that help any I hope so:) if not tell me I will have another strategy
 
        
             
        
        
        
A straight line needs two pieces of information to be identified, a gradient and a y-intercept (technically any point will do but the y-intercept is particularly convenient if we have it).
The gradient is calculated by taking two points on the line, and dividing the change in y-coordinate by the change in x-coordinate between them. I'm going to take the points (0,-3) and (2,-2).
The change in y-coordinate is (-2) - (-3) = 1
The change in x-coordinate is (2) - (0) = 2. 
Gradient = m = 1/2
Next we identify the y-intercept, the value of y when x = 0. This value is -3, and we call it c.
The equation of a line in slope-intercept form is y = mx + c. Slotting in the values for m and c we have ascertained, we find that the equation of this line is:
y = (1/2)x - 3
I hope this helps :)