So I'm assuming that you're taking Calculus.
The first thing you want to do is take the integral of f(x)...
Use the power rule to get:
4X^2-13X+3.
Now solve for X when f(x)=0. This is because when the slope is 0, it is either a minimum or a maximum(I'm assuming you know this)
Now you get X=0.25 and X=3. Since we are working in the interval of (1,4), we can ignore 0.25
Thus our potential X values for max and min are X=1,X=4,X=3(You don't want to forget the ends of the bounds!)
Plugging these value in for f(x), we get
f(1)=2.833
f(3)=-8.5
f(4)=1.667
Thus X=1 is the max and X=3 is the min.
So max:(1,2.833)
min:(3,-8.5)
Hope this helps!
Answer:
60
Step-by-step explanation:
Look at the attachment
Answer:

Step-by-step explanation:

Don't mind the 
Answer: The rate of change decreased.
Step-by-step explanation:
Assume that 100% = 45 sales and 35% = X sales amount
You can create a ratio to help you solve for x
45 = 100%
x = 35 %
Which is equal to this fraction: (45/x) = (100/35)
Solving for X by cross multiplying and dividing by 100:
[(45)(35)] / 100 = X = 15.75 = 16 sales (rounded up)
You would need at least 16 sales to increase sales total by 35%