```Question 197355

{{{system(7x-9y=-18,9y-7x=18)}}}

In order to graph these equations, we must solve for y first.

Let's graph the first equation:

{{{-9y=-18-7x}}} Subtract {{{7x}}} from both sides.

{{{y=(-18-7x)/(-9)}}} Divide both sides by {{{-9}}} to isolate {{{y}}}.

{{{y=(7/9)x+2}}} Rearrange the terms and simplify.

Now let's graph the equation:

{{{drawing(500,500,-10,10,-10,10,
grid(0),
graph(500,500,-10,10,-10,10,(7/9)x+2)
)}}} Graph of {{{y=(7/9)x+2}}}.

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Now let's graph the second equation:

{{{9y=18+7x}}} Add {{{7x}}} to both sides.

{{{y=(18+7x)/(9)}}} Divide both sides by {{{9}}} to isolate {{{y}}}.

{{{y=(7/9)x+2}}} Rearrange the terms and simplify.

Now let's graph the equation:

{{{drawing(500,500,-10,10,-10,10,
grid(0),
graph(500,500,-10,10,-10,10,(7/9)x+2)
)}}} Graph of {{{y=(7/9)x+2}}}.

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Now let's graph the two equations together:

{{{drawing(500,500,-10,10,-10,10,
grid(1),
graph(500,500,-10,10,-10,10,(7/9)x+2,(7/9)x+2)
)}}} Graph of {{{y=(7/9)x+2}}} (red). Graph of {{{y=(7/9)x+2}}} (green)

From the graph, we can see that one line is right on top of the other one, which means that they intersect an infinite number of times. So there are an infinite number of solutions. This means that the system of equations is consistent and dependent.```