Question

It is given that -1 is one zero of the polynomial x^3+2x^2-11x-12. Find all other zeros.

Answer 1

Answer:

zeros of the polynomial are −1, 3 and −4

Step-by-step explanation:

Let f(x)=x  

3

+2x  

2

−11x−12

Given : −1 is a zero of the polynomial , which means (x+1) is a factor of f(x)

 

Dividing f(x) by (x+1) we get

f(x) becomes:

f(x)=(x+1)(x  

2

+x−12)

=(x+1)(x  

2

+4x−3x−12)

=(x+1)(x−3)(x−4)

if f(x)=0

⇒(x+1)(x−3)(x+4)=0

either (x+1)=0 or (x−3)=0  or (x+4)=0

x=−1 or x=3 or x=−4

zeros of the polynomial are −1, 3 and −4

hope this helps you

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