To expand two terms such as these, we can use the method called FOIL (stands for First, Outer, Inner, Last). Here is what I mean:
We have two terms: (x - 2)(x - 1)
We should first multiply the First two terms of each term in order to complete the F stage:
(x)*(x) =

So then, we take the two outer terms and multiply them together to complete the O stage:
(x)*(-1) = -x
So far we have two things that we have calculated; at the end of the FOIL process we will have four.
To keep going with the FOIL, we now multiply the two inner terms to complete the I stage:
(-2)*(x) = -2x
Last but not least, we need to complete the L stage - so we multiply the two last terms of each term:
(-2)*(-1) = 2
Now that we have our four terms, let us add them together and combine like terms:

Since -x and -2x both have the x portion in common and they are added together, we can add them to create one single term:
-x + (-2x) = -3x
So now that we have our terms completed, we can combine into one polynomial equation:

or
The answer is: Find the mean of the differences with the other numbers in the set<span>. Add the squared differences and then divide the total by the number of items in </span>data<span> in your </span>set; t<span>ake the square root of this mean of differences to </span>find<span> the standard </span>deviation.
Step 1: Find the slope
(y-y)/(x-x) = (8-8)/(9+4) = 0
Step 2: Substitute into the slope intercept equation
y - y = m(x - x)
y - 8 = 0(x - 9)
If the problem just wants plain, slope intercept form, then this is your answer.
If not, y = 8