Number graph ranging from negative eight to eight on the x axis and negative eight to eight on the y axis. two lines that are perpendicular to each other intersect at (three, zero). the line with a positive slope is labeled a and the line with a negative slope is labeled b. use the graph to state the solution for the system. x – y = 3 (line a) x + y = 3 (line b) a. (0, 3) b. (–3, 0) c. (0, –3) d. (3, 0)