1) A. since, if you put the numbers into the equation (one at a time) the equation = 0 each time, which is true. 2) I think I've been taught to complete the square slightly differently x^2 - 18x - 17 = 0 (x-9)^2 - 81 -17 = 0 (x-9)^2 - 98 = 0 I hope you can get something from that