Question

Q.18. If one zero of the polynomial x2 + 6x + 9 is - 3, then other zero-
(i). 3
(ii). - 3
(iii). O
(iv). 9​

Answer 1

Answer:

-3

Step-by-step explanation:

Sum of the zeros of a quadratic polynomial a$x^{2}$ + b$x^{}$ + c =0 is given by (-b/a) .

Here , b= 6 and a = 1

Sum of the roots = -(6/1) = -6

Let the other zero be k .

k + (-3) = -6

k= -3

Alternate method

$x^{2}$ + 6$x^{}$ + 9 = 0

$(x+3)^{2}$ = 0

$x^{}$ = -3, -3

Hence the other root is also -3 .

Hope this helps.

Answer 2

Answer:

Option (ii) –3

The other zero of the polynomial is (–3).

Step-by-step explanation:

Factorize x² + 6x + 9

$\longrightarrow$ x² + 3x + 3x + 9

$\longrightarrow$ x(x + 3) + 3(x + 3)

$\longrightarrow$ (x + 3)(x + 3)

Zeros are =

$\longrightarrow$ x + 3 = 0

$\longrightarrow$ x = –3

$\longrightarrow$ x + 3 = 0

$\longrightarrow$ x = –3

Zeros of polynomial are (–3) and (–3).

Therefore, the other zero of the polynomial is (–3).