Answer:
Yes. No graph paper.
Step-by-step explanation:
Let's say the 3 points are A, B, C.
If A, B and C lie on one line then 

Hence, they lie on one line.
You don't need to use a graph paper to prove it.
 
        
             
        
        
        
Answer:
roots: 1 and 3
k = 3
Step-by-step explanation:
2 roots: p and p+2
(x-p) (x-p-2) = x² - 4x + k
x² -2px -2x + p² + 2p = x² - 2 (p+1)x + (p² + 2p) = x² -4x + k
-2 (p+1) = -4
p+1 = 2
p = 1   ... root 1
p' = 1+2 = 3   ... root 2
k = p² + 2p = 3
check: (x-1) (x-3) = x² - 4x + 3 = x² - 4x + k
 
        
             
        
        
        
Answer:
9 
Step-by-step explanation:
nine is the highest number in each of them