Answer/Step-by-step explanation:
1. 
Apply the Quotient rule: i.e. 

2. 
Apply the product rule: i.e.
.


Apply the negative exponent rule: i.e. 


3. 
Apply product rule




4. 
Apply the rules of 1 and quotient rule



A) Original price : y =10.x
Cheaper brand : y = 7x
The original box is $3 more than the cheap one. Proof:
Suppose 1 box is bought of each (x=1),original will cos10 & the cheaper $7
b) Each time he buys a cheap brand he save $3 ($10-$7), on 5 cheap boxes, he would save $3 x 5 boxes = $15
One liter is 33.814 so do (n x 33.814)
Volume = pi x radius squared x height
v=3pixr^2x3
v=27pi