Question

If √5 and -√5 are two zeros of the polynomial x3 +3x2-5x-15 find it's third zero

Answer 1

Answer:

-3

Step-by-step explanation:

Refer to the attachment

Hope it helps you...!!

Answer 2

Step-by-step explanation:

Step-by-step explanation:

Hello !!!

Here, x^3 +3x^2 -5x -15 = 0 is the given polynomial.

The two zeroes = √5 and -√5

x^3 + 3x^2 - 5 x - 15

= √5 -√5

= (x-√5) (x+√5)

= x^2 + √5x - √5x -5

= x^2 - 5

Now Dividing we get,

x^2 - 5 ) x^3 + 3x^2 - 5x - 15 ( x + 3

x^3 - 5x

- +

---------------------------------

3x^2 - 15

3x^2 - 15

- +

---------------------------------

0

Hence your third zero = x = -3

I hope it help you.

Stay safe and keep smiling mate .

Bye.....