

This is a way to factoring trinomials (there exist different equivalent methods).
Multiply the trinomial but the term accompanying
. This is the second line. Then, you could take the square of the
, ant try to create a factor () () that will correspond to the expression in the second line. That is, we want 
In ? we put the corresponding numbers that, if we multiply them we will obtain 42, and if we add them we will obtain 13. This numbers are 6 and 7. Then, we have 
The last step is divide by the number that we multipy in the first step.
Hello,
we must multiply the number of pages by the number of cards that hold each page to find the total number of card that she can organize, so:
5*18=90
She can organize 90 cards, but she has 95, then SHE DOESN'T HAVE ENOUGHT PAGES TO ORGANIZE THEM.
If we evaluate the function at infinity, we can immediately see that:

Therefore, we must perform an algebraic manipulation in order to get rid of the indeterminacy.
We can solve this limit in two ways.
<h3>Way 1:</h3>
By comparison of infinities:
We first expand the binomial squared, so we get

Note that in the numerator we get x⁴ while in the denominator we get x³ as the highest degree terms. Therefore, the degree of the numerator is greater and the limit will be \infty. Recall that when the degree of the numerator is greater, then the limit is \infty if the terms of greater degree have the same sign.
<h3>Way 2</h3>
Dividing numerator and denominator by the term of highest degree:



Note that, in general, 1/0 is an indeterminate form. However, we are computing a limit when x →∞, and both the numerator and denominator are positive as x grows, so we can conclude that the limit will be ∞.