Question

For what value of k, is 3 a zero of the polynomial 2x² + x + k?

Answer 1

We know that if  `x = a` is zero polynomial, and then  x - a is a factor of  f(x)

Since 3 is zero of   f (x)

Therefore x - 3 is a factor of  f(x)

Now, we divide `f(x)=2x^2+ x+ k`  by `g (x) = x-3`  to find the value of k

Now, remainder = 0

`k + 21 = 0 `

` k = -21`

Hence, the value of k is = -21