What is the sum of all possible values of for which x^2 + kx - 10x + 36 is the square of a binomial?
(x+6)^2 = x^2 + 12x + 36 so 12x = kx-10x
(x-6)^2 = x^2 -12x + 36 so -12x = kx-10x solve for k in both instances and add them...
+36916 
