What is the sum of all possible values of k for which x^2 + kx - 9x + 25 is the square of a binomial?

What are the interpretations of the line 3x - 15y = 60? x-intercept y-interception a: x 20 - y -4 b: x 5 - y 20 c: x -3 - y 15 d: x -4 - y 20