Use the distributive property to multiply 7(c+4)  
then answer is 7c+28 
 
        
             
        
        
        
<span><span><span>10<span>(<span>1−23</span>)</span></span><span>(2)</span></span>+13</span><span>=<span><span><span><span>(10)</span><span>(<span>−22</span>)</span></span><span>(2)</span></span>+13</span></span><span>=<span><span><span>(<span>−220</span>)</span><span>(2)</span></span>+13</span></span><span>=<span><span>−440</span>+13</span></span><span>=<span>−<span>427</span></span></span>
        
                    
             
        
        
        
Step-by-step explanation:
Let 
x
 be the kg of coffee of brand A in the mix and 
y
 be the kg of coffee of brand B in the mix.
The total kg must be 
50
.
x
+
y
=
50
The cost per kg of the mix must br 
$
7.20
. For this, the total cost of the mix will be 
6
x
+
8
y
, so the total cost per kg of the mix will be 
6
x
+
8
y
50
.
6
x
+
8
y
50
=
7.20
Now that we have our two equations, we can solve.
6
x
+
8
y
=
7.20
⋅
50
6
x
+
8
y
=
360
From the first equation, we can multiply both sides by 
6
 to get:
6
x
+
6
y
=
300
Subtracting, we get:
2
y
=
60
y
=
30
Thus, we need 
30
 kg of brand B in our mix. This means that 
50
−
30
=
20
 kg will be of brand A.