To solve this problem just do the following, 
x+9=-12
   -9    -9
x=-21
Check
-21+9=-12 = True 
Hope this helps!=) 
        
                    
             
        
        
        
Guys help me I’m stuck in this question also it’s in my homework
        
             
        
        
        
For example: 18-inch princess necklace made with 4mm beads: 18 x 25.4 ÷ 4 = 114.3. 32-inch opera necklace made with 10mm beads: 32 x 25.4 ÷ 10 = 81.2.
Necklace?
Type	Length
Collar	14 to 17 inches
Choker	16 to 18 inches
Princess	17 to 19 inches
Matinee	20 to 25 inches
        
             
        
        
        
<u>Solution</u>:
3y = -9x - 22
y = -3x - 22/3
The graph parallel to this graph (9x + 3y = -22) should have a gradient of -3
In the choices above i.e A,B,C & D there is not a single equation with a gradient equal to -3.