Question

If 3 is the zero of the polynomial 2xsquare+x+k find the value of k

Answer 1

Answer:

p(x)= 2x²+x+k

p(3)=2(3)²+3+k=0

18+3+k=0

21+k=0

k=-21

Answer 2

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 polynomial