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

Answer:
1). 24
2). 8
Explanation:
1).
285$ - 45$ = 240$
240$/10 = 24$
Therefore, he pays 24$ a month.
2).
Let x be the number than triple:
3x - 5 = 19
3x = 19 + 5
3x = 24
x = 24/3
x = 8
Answer: 56
Step-by-step explanation:
I think that the answers are 4, 4 and 25 respectively