Question

(ii) x - 3x? - 9x - 5​

Answer 1

Step-by-step explanation:

We will find one of the zeros of the expression x3 – 3x2 – 9x – 5 and use long division to find the other zeros.

Explanation:

Substitute 5 for x in x3 – 3x2 – 9x – 5

53 – 3(5)2 – 9(5) – 5 = 125 - 75 - 45 - 5 = 0

So, 5 is zero of the expression x3 – 3x2 – 9x – 5

This means (x - 5) is a factor of x3 – 3x2 – 9x – 5

Divide x3 – 3x2 – 9x – 5 by x - 5

This means x3 – 3x2 – 9x – 5 = (x - 5) (x2 + 2x + 1) = (x - 5) (x+1)2

Therefore, the factorization of x3 – 3x2 – 9x – 5 is (x - 5) (x+1)2