Question

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

Answer 1

hope this helps u......

Answer 2

Given,

• The zero of a polynomial $2x^2+x+k$ is 3.

To find,

• We have to find the value of k.

Solution,

We can simply find the value of k by substituting the value of x = 3 in $2x^2+x+k$.

Since x = 3 is a zero of the polynomial $2x^2+x+k$, then $2x^2+x+k$ must satisfy x = 3.

p(x) =  $2x^2+x+k$,

p(3) = 2(3)² + 3 +k

      = 2(9) + 3+k

      = 18 + 3+k

       = 21 + k

Since x = 3 is a zero of the polynomial $2x^2+x+k$, then $2x^2+x+k$ must satisfy x = 3, then

        21 + k = 0

                k = -21  

Hence, for k = -21 3 is a zero of the polynomial $2x^2+x+k$.