Question

If 3 is a zero of polynomial x^2+2x+k
find the value of K and other zeroes​

Answer 1

Answer:

k=-15, x=-5

Step-by-step explanation:

Given :- x = 3

• It is given that 3 is Zero of polynomial

x² + 2x + k. When we put value of x as 3 in the polynomial we get 0 as resultant.

x² + 2x + k = 0

( 3 )² + 2× 3 + k = 0

9 + 6 + k = 0

k = - 15

The required polynomial is

x² + 2x - 15 = 0

x² + 5x - 3x - 15 = 0

x ( x + 5 ) - 3 ( x + 5 ) = 0

( x - 3 ) ( x + 5 ) = 0

• ( x - 3 ) = 0

x = 3 ( given )

• ( x + 5 ) = 0

x = - 5

- 5 is the second Zero of polynomial.

Answer 2

Step-by-step explanation:

x^2+2x+k=0

(3)^2+2(3)+k=0

9+6+k=0

k= -15

Therefore, the required polynomial is:-

x^2 + 2x -15 =0

x^2 +5x -3x-15=0

x(x+5)-3(x+5)

(x-3) (x+5) =0

x-3=0 and x+5=0

x=3 and x=-5