Given a polynomial
and a point
, we have that

We know that our cubic function is zero at -4, 0 and 5, which means that our polynomial is a multiple of

Since this is already a cubic polynomial (it's the product of 3 polynomials with degree one), we can only adjust a multiplicative factor: our function must be

To fix the correct value for a, we impose
:

And so we must impose

So, the function we're looking for is

Full Question: Below is the diagram of the base of gazebo. Hunter is building for his backyard. He plans on gazebo having a height of 4 meters with a pyramid shaped roof that is an additional 2 meters high. He needs to order shingles for the roof and needs to know how much area is covered by shingles.
Answer:

3x2+4x=2
6+4x=2
-6 -6
4x=-4
4 4
x=-1
The answer should. Bey=5/6x+6