Question

q1pls tell fast call me at 9315175042..

Answer 1

hey!!
see this attachment.
THIS WILL HELP YOU.
:)

Answer 2

Let 3 be the zero of the polynomial.
Putting x = 3 in equation 
2x² + x + k = 0
2×3² + 3 + k = 0
18 + 3 + k = 0
k = -21