Part A: 
We see that this pair of equations has 1 solution. On a graph, the solutions of 2 (or more) lines is where the lines intersect. In this case, since these lines intersect 1 time, they have 1 solution. 
Part B:
As previously mentioned, the solutions of multiple lines is where the lines intersect. In this case, since they intersect at (4,4), that is the solution.
 
        
             
        
        
        
Wait it says ur in high school so u can't be over 30. that isn't possible. So what's the problem here? not good at math.
        
             
        
        
        
Answer:
hardd  sorry 
Step-by-step explanation:>..
 
        
             
        
        
        
Answer:
t=3.2c
Step-by-step explanation: