Factoring by grouping usually pairs up the first 2 sets of expressions with the second 2 sets. Ours looks like this, then:

. If we factor out the common x-squared in the first set of parenthesis, along with factoring out the common 5 in the second set, we get this:

. Now the common expression that can be factored out is the (x-9). When we do that, here's what it looks like:

. I'm not sure how far you are going with this. You could set each of those equal to 0 and solve for x in each case. The first one is easy. If x - 9 = 0, then x = 9. The second one involves the imaginary i since x^2 = -5. In that case,

. Hopefully, in what I have given you, you can find what you're looking for.
Answer:
$19.08
Step-by-step explanation:
18 + 6% = (18 x 1.06) = 19.08
We have been given the function 
Convert this expression in difference of cubes form.

Now, in order to find the factors, we can apply the difference of cubes form, which is given by

On applying this formula, we get

Hence, the factors of the given expression are

Out of the given option, A is the correct option.
x^5 − 4 is the required factor.
Answer:
D. (7,5)
Step-by-step explanation:
Imagine a full parallelogram, complete the shape from there
I assume you mean one that is not rational, such as √2. In such a case, you make a reasonable estimate of it's position, and then label the point that you plot.
For example, you know that √2 is greater than 1 and less than 2, so put the point at about 1½ (actual value is about 1.4142).
For √3, you know the answer is still less than 4, but greater than √2. If both of those points are required to be plotted just make sure you put it in proper relation, otherwise about 1¾ is plenty good (actual value is about 1.7321).
If you are going to get into larger numbers, it's not a bad idea to just learn a few roots. Certainly 2, 3, and 5 (2.2361) and 10 (3.1623) shouldn't be too hard.
Then for a number like 20, which you can quickly workout is √4•√5 or 2√5, you could easily guess about 4½ (4.4721).
They're usually not really interested in your graphing skills on this sort of exercise. They just want you to demonstrate that you have a grasp of the magnitude of irrational numbers.