The roots of f(x) are {0, 3, -4}. You've got them as {-3, 4}, which is not correct.
Draw another set of coordinate axes and place dark dots at (0,0), (3,0) and (-4,0). These dots represent the roots (solutions) of the given polynomial.
Note that we have a repeated (double) root at x=3, which is given away by the exponent 2 of (x-3).
A basic way of sketching this graph is described as follows:
Evaluate the function (find y) for several x-values other than (0, 3 and -4):
Choose (for example) {-5, -2, -1, 1, 2, 4}
If you'll find the y-value for each of these x-values and plot the resulting points, you should see the shape of the graph. Draw a rough graph thru these points. If any doubt remains about what the graph looks like at particular x-values, calculate and plot more points, e. g., at {-2.5, -1.5, ...}.
If you're taking calculus, consider applying the First- and Second-Derivative tests to determine concavity, maximum, minimum, etc.
Without considering the sign:
It's sigma(1 to 5, 5k+2)
Since the first item is minus, you simply add (-1)^k
So it's sigma(1 to 5, (-1)^k * (5k+2)
I choose A
Answer:
a) Figure attached
b) If we see the scatter plot we can conclude that the possible relation between x and y is linear and with a positive correlation since when the values of x increases the values for y increases as well.
c) 
We can find the numerator like this:

And then:

d)
Step-by-step explanation:
Part a
For this part we use excel in order to create the scatterplot and we got the result on the figure attached.
Part b
If we see the scatter plot we can conclude that the possible relation between x and y is linear and with a positive correlation since when the values of x increases the values for y increases as well.
Part c
The sample covariance is defined as:

We can find the numerator like this:

And then:

Part d
The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.
And in order to calculate the correlation coefficient we can use this formula:
For our case we have this:
n=5
So then the correlation coefficient would be r =0.693
20(1+3)
The greatest common factor between the two numbers is 20, because both numbers are divisible by 20. It cannot be any higher because 20 is one of the numbers itself. You divide this out of both numbers and put it outside the function with the use of parenthesis.
Answer:
(3,2)
Step-by-step explanation:
y = 4x – 10
y = 2
Substitute the second equation into the first
2 = 4x-10
Add 10 to each side
2+10 = 4x-10+10
12 = 4x
Divide each side by 4
12/4 =4x/4
3 = x
The solution is
(3,2)