Answer:
(x-7)/(x+2)
Step-by-step explanation:
(x-7)(x+7)/(x+7)(x+2)
(x-7)/(x+2)
We are asked to determine the correlation factor "r" of the given table. To do that we will first label the column for "Quality" as "x" and the column for "Easiness" as "y". Like this:
Now, we create another column with the product of "x" and "y". Like this:
Now, we will add another column with the squares of the values of "x". Like this:
Now, we add another column with the squares of the values of "y":
Now, we sum the values on each of the columns:
Now, to get the correlation factor we use the following formula:

Where:

Now we substitute the values, we get:

Solving the operations:

Therefore, the correlation factor is 0.858. If the correlation factor approaches the values of +1, this means that there is a strong linear correlation between the variables "x" and "y" and this correlation tends to be with a positive slope.
<h2>
Answer:</h2>
<u>The answer is </u><u>(C) 4</u>
<h2>
Step-by-step explanation:</h2>
According to the rule of BODMAS
We will first do division then Multiplication then addition and in the last we do subtraction
So
12 ÷ 2 + 4 – 2 × 3 will be done as
= (12 ÷ 2) + 4( – 2 × 3)
= 6+4-6
= 4
Answer:
Part A) see the explanation
Part B) 
Step-by-step explanation:
Part A)
we know that
A relationship between two variables, x, and C, represent a proportional variation if it can be expressed in the form
or 
Let
C ---> is the total cost (represent the output or dependent variable)
x ----> is the number of books (represent the input or independent variable)
In this problem
we have a proportional relationship between the variables x and C
Part B) we know that
The linear equation is given by

The constant of proportionality k is the same that the slope or unit rate of the linear equation
In this problem the constant k is given

so

For x=12 books
substitute in the equation and solve for C

In function notation

Answer:
the answer is probably inverse or joint or combined,really haven't seen this type of variation before