the graph of f(x) = 4x3 – 13x2 + 9x + 2 is shown below.
how many roots of f(x) are rational numbers?
a.) 0
b.) 1
c.) 2
d.) 3

One rational root.

B is correct.

Step-by-step explanation:

Given: The graph of

First we factor the given function.

Factor of f(x)

f(2)=0 , x-2 must be factor of f(x)

Because f(2)=0

So, x=2 is rational root of f(x)

Now we find another root using quadratic formula.

where, a=4, b=-5 and c=-1

Another roots are,

So, these are irrational root because is irrational.

Hence, The given function has 1 rational root and 2 irrational roots.

I am going to show you the easiest, quickest and most direct way of doing it.
Take in account:
1) the result of applying a 20% discount is the same that multiplying times a factor of 0.8, which results from (100 - 20) / 100 = 80 /100 = 0.8
2) adding a 6.5% of tax is the same that multiplyiing by a factor of 1 + 6.5/100 = 1 + 0.065 = 1.065
With that
Super Sport store:
12  * 72.50 * 0.8 * 1.065 = 741.24 
Double Dribble
Use that a disscount of 9% results in a factor o 0.91.
I amended the shipping fee data to 5.99 per pair of shoes.
12*54.75*0.91 + 5.99*12 = 669.75
Difference: 741.24 - 669.75 = 71.48