[tex]{\huge {\mathfrak {Answer :-}}} [/tex]
➡️ x^2 + kx - 8 = 0
Or, (4)^2 + k(2) - 8 = 0
Or, 2k = - 8
Or, k = - 8/2 = - 4
[tex] <b>[/tex] That's it..