ANSWER:

STEP-BY-STEP EXPLANATION:
We have the following expression:

In order to operate, we must first break the parentheses and then group similar terms, like this:
Answer:
(a) The sample variance is 16.51
(a) The sample standard deviation is 4.06
Step-by-step explanation:
Given

Solving (a); The sample variance.
First, calculate the class midpoints.
This is the mean of the intervals.
i.e.





So, the table becomes:

Next, calculate the mean




Next, the sample variance is:

So, we have:



The sample standard deviation is:



Answer:
13x² - 4x
Step-by-step explanation:
3x + 4x² - 7x + 9x² ← collect like terms
= (4x² + 9x² ) + (3x - 7x)
= 13x² + (- 4x)
= 13x² - 4x
For part B
the fixed cost is 500 dollars because it is a set inital amount, the varibale cost is .15 because it is the cost dependent on something else (per indicated variable part)
y=.15x+500
.15 cents per flyer, add 500 because that is the set amount it costs to even create the flyer
Plug in 500 for the equation
y=.15(500)+500
y=75+500
y=575
for part a
b=ka for direct variations so the direct one is C - two items directly multiplied
y=mx+b for partial variation so its A,D - basically the equation of a line
A is neither - shows neither of these relationships