Question 1044084
The only factorizations of {{{ x^2+kx+15 }}} with integer coefficients are

(x+1)(x+15),
(x+3)(x+5), 
(x-1)(x-15), and 
(x-3)(x-5).


The coefficient of x in each case is 16, 8, -16, and -8, respectively, and their product is {{{16*8*-16*-8 = 16384}}}.