Question

from what value of k 3 is a zero of the polynomial 2 X square + X + k

Answer 1

P(x) = 2x^2 +x + k

=> P(3) = 0

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

=> 18+3 + k = 0

=> 21 +k = 0

=> k = - 21

Answer 2

Answer:

The value of k is -21

Step-by-step explanation:

Given that 3 is the zero of the polynomial

$P(x)=2x^2+x+k$

we have to find the value of k.

As 3 is the zero of the polynomial therefore by remainder theorem

$P(3)=0$

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

$2(9)+3+k=0$

$18+3+k=0$

$21+k=0$

Subtracting 21 from both sides

$k=-21$

Hence, the value of k is -21