Step-by-step explanation:
Part A:
Let  be the number of mittens and
 be the number of mittens and  be the number of scarves. Then we have the inequalities:
 be the number of scarves. Then we have the inequalities: 
 <em>This says Nivyana and Ana cannot make more than 30 scarves</em>
 <em>This says Nivyana and Ana cannot make more than 30 scarves</em>
 <em>This says that</em> <em>Nivyana and Ana have to earn at least $1000.</em>
 <em>This says that</em> <em>Nivyana and Ana have to earn at least $1000.</em>
Part B: 
The graph is attached.
Notice that the graphs of the inequalities are solid lines, this just means that the points on these lines included to the solutions of each inequality.
The darker shaded region and the solid lines bounding it, are the solutions to the inequalities because that's where the values common to both inequalities are found.
Part C:
From the graph we get two possible solutions:
15 scarves & 10 mittens
25 scarves & 5 mittens.
These two points lie on the solid lines that bound the darker shaded region<em> (I picked those points to stress that the lines bounding the dark region are also solutions.)</em>
 
        
             
        
        
        
Answer:
a = -4, b = 3 and c = 6 (OR)
a = -4, b = -3 and c = 6
Step-by-step explanation:

Add 16 to both sides.


 or
 or 
 or
 or 
 or
 or 
Therefore, a = -4, b = 3 and c = 6 (OR)
a = -4, b = -3 and c = 6
 
        
                    
             
        
        
        
43 47 53 59 are the prime numbers