Question

Find the equation for a polynomial f(x) that satisfies the following:

- Degree 5
• Root of multiplicity 2 at x = 3
- Root of multiplicity 1 at x = 1
• Root of multiplicity 2 at x = 3
- y-intercept of (0, -162)

Answer 1

Root x= 3 of multiplicity 2, it means we can factor it with : (x-3)²

Root x = 1, of multiplicity 1, it means we can factor this polynomial with : (x-1)

Root x = -3, of multiplicity 2, it means we can factor this polynomial with : (x+3)²

Finally we get this expression : (x-3)²(x+3)²(x-1)

This expression is a polynomial of degree 5 but what is the y intercept of it ?

Basically, we need to replace x by zero and the value of the expression will be the y intercept :

let x = 0

then ,

(0-3)²(0+3)²(0-1) = 9*9*(-1) = -81 #-162

We need an y intercept of value = -162

Thus we simply need to multiply by 2, and finally f(x) = 2(x-3)²(x+3)²(x-1)

satisfies all the required condition

Good Luck