<span>First. <u>Finding the x-intercepts of </u>
</span><span>
Let be the change in water level. So to find the x-intercepts of this function we can use The Rational Zero Test that states:
To find the zeros of the polynomial:
We use the Trial-and-Error Method which states that a factor of the constant term:
can be a zero of a polynomial (the x-intercepts).
So let's use an example: Suppose you have the following polynomial:
where the constant term is
. The possible zeros are the factors of this term, that is:
.
Thus:
</span>
<span>
From the foregoing, we can affirm that
are zeros of the polynomial.
</span>Second. <u>Construction a rough graph of</u>
Given that this is a polynomial, then the function is continuous. To graph it we set the roots on the coordinate system. We take the interval:
![[-2,-1]](https://tex.z-dn.net/?f=%5B-2%2C-1%5D)
and compute
where 
is a real number between -2 and -1. If 
, the curve start rising, if not, the curve start falling. For instance:
Therefore the curve start falling and it goes up and down until
and from this point it rises without a bound as shown in the figure below
</span><span>
Let
To find the zeros of the polynomial:
We use the Trial-and-Error Method which states that a factor of the constant term:
can be a zero of a polynomial (the x-intercepts).
So let's use an example: Suppose you have the following polynomial:
where the constant term is
Thus:
</span>
From the foregoing, we can affirm that
</span>Second. <u>Construction a rough graph of</u>
Given that this is a polynomial, then the function is continuous. To graph it we set the roots on the coordinate system. We take the interval:
and compute
Therefore the curve start falling and it goes up and down until