If you use the distributive property, you will multiply 4 by 2x to get 8x and 4 by -4 to get -16. 
8x-16=8x+k
If you want infinitely many solutions the equations on both sides of the equal sign need to be the same. So, k would need to be -16.
        
                    
             
        
        
        
Answer:
C = 43.98 in
Step-by-step explanation:
Radius = 7
C / d = pi
C = pi * d
C = pi * 14
 
        
             
        
        
        
Answer:
D) 171 cm²
Step-by-step explanation:
You don’t actually need to decompose it.  You could just do it as a trapezoid:
(15+23)/2=19
19x9=171
If you want to decompose it into 2 triangles and a rectangle:
10=15x9=135
1/2(3)(9)=13.5
1/2(5)(9)=22.5
135+13.5+22.5=171 also
 
        
             
        
        
        
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