Answer:
c + k = - 1
Explanation:
given a quadratic equation in standard form : ax² + bx + c = 0 : a ≠ 0
Then the sum of the roots = -
and
The product of the roots =

- x² - x + 6 = 0 is in standard form
with a = - 1, b = - 1 and c = 6
The roots are c and k, hence
c + k = -
= - 1