80 - 2p 
You use the distributive property
        
             
        
        
        
Answer:
(5,-1) 
Step-by-step explanation:
when reflecting over the x-axis:
(x,y) → (x,−y)
get coordinates of D: (5,1) 
get coordinates of D': (5,-1) 
hope this helped!
 
        
             
        
        
        
Answer:
y=2/7x+19/7
Step-by-step explanation:
Slope = m = (y₂-y₁)/(x₂-x₁) = (5-3)/(8-1) = 2/7
Therefore, our equation so far is y=2/7x+b where we can calculate b, the y-intercept by plugging in one of our given points [I used (1,3)]:
y=2/7x+b
3=2/7(1)+b
3=2/7+b
21/7=2/7+b
19/7=b
Therefore, our final equation is y=2/7x+19/7
 
        
             
        
        
        
Volume of a sphere is 4/3pi∗r3. r is half the diameter.