Answer:

Step-by-step explanation:
<u>Equation of a Polynomial</u>
Given the roots x1, x2, and x3 of a cubic polynomial, the equation can be written as:

Where a is the leading coefficient.
We know the three roots of the polynomial -6, -3, and 1, thus:

Since the y-intercept of the polynomial is y=90 when x=0:
90=a(0+6)(0+3)(0-1)
90=a(6)(3)(-1)=-18a
Thus
a = 90/(-18) = -5
The polynomial is:

We must write it in standard form, so we have to multiply all of the factors as follows:




