how do I solve this system graphically? 3x-y = 9, 9x- 3y = 9

Question

Solve this system graphically. Write the answers as an ordered pair. must graph this. If it is unsolvable or the answer is indefinite, must state that. Place on a graph.

Answer 1

3x - y = 9

y = 3x - 9

.

9x - 3y = 9

3y = 9x - 9

y = 3x - 3

.

Slopes are both 3, so the lines are parallel.  Y-intercepts are different, so the lines are separate from each other.  We should end up with 2 separate parallel lines.  The lines never cross, so there is no solution.  Let's graph that:

Here's the graph on graphsketch.com:  http://graphsketch.com/?eqn1_color=1&eqn1_eqn=3x%20-%209&eqn2_color=2&eqn2_eqn=3x%20-%203&eqn3_color=3&eqn3_eqn=&eqn4_color=4&eqn4_eqn=&eqn5_color=5&eqn5_eqn=&eqn6_color=6&eqn6_eqn=&x_min=-17&x_max=17&y_min=-10.5&y_max=10.5&x_tick=1&y_tick=1&x_label_freq=5&y_label_freq=5&do_grid=0&do_grid=1&bold_labeled_lines=0&bold_labeled_lines=1&line_width=4&image_w=850&image_h=525