Answer:
I think its the lifo method im not sure but i had a question like this in class
 
        
             
        
        
        
A. You can factor it to those terms
        
             
        
        
        
I don't see any answer choices, but because it already gives you x and y, all you have to do is plug them into the equation.
-(5)-(6)+z=0
combine like terms
-11 + z = 0
add 11 to both sides
z = 11 is your answer
        
                    
             
        
        
        
20× 8 = 160
160 + 2x > or = 500
-160--------------- -160
2x > or = 340
÷2------------÷2
x > or = 170
She has to sell at least 170 cupcakes to make $500 in profit.
Hope this helps!