Question

for what value of k ,is 3 a zero af the polynomial 2x^2+x+k​

Answer 1

Answer:

K = - 21

Step-by-step explanation:

2x^2 + x + k = 0, for x = 3

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

2(9) + 3 + k = 0

18 + 3 + k = 0

k + 21 = 0

k = - 21

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Answer 2

Answer:

Thus, for k = -21, 3 is a zero of the polynomial.

Step-by-step explanation:

The polynomial is :

2x² + x + k

Suppose, 3 is zero of polynomial for some value of k, then

2x² + x + k = 0

∴2(3)² + 3 + k = 0           (Putting x = 3)

∴2*9 + 3 + k = 0

∴18 + 3 + k = 0

∴21 + k = 0

∴k = -21

Thus, for k = -21, 3 is a zero of the polynomial.