Answer:
3
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
14
Step-by-step explanation:
We can make this and equation 
x • y = 1260
x = 3y +48
Our equation is 
(3y +48)y = 1260
We get y = 14
 
        
             
        
        
        
The derivative of f(x) at x=3 is 2x=6 approaching from the left side (apply power rule to y=x^2). The derivative of f(x) at x=3 is m approaching from the right side. In order for the function to be differentiable, the limit of derivative at x=3 must be the same approaching from both sides, so m=6. Then, x^2=mx+b at x=3, plug in m=6, 9=18+b, so b=-9.
        
                    
             
        
        
        
Since there are 21 questions and one is extra credit, the fraction is 21/20. Divide it to get 1.05. In percent, this is 105%. Hope this helps!