##### solving systems by graphing

label Algebra
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I am stuck on this problem and I have a quiz with these problems tommorow! How do I solve 3x+4y=8 and x-2y=6 and graph it?

Oct 9th, 2015

Ok first you solve for y (y=x format)

3x+4y=8

4y=8-3x

Divide by 4

y=2-(3/4)x

now you know the slope is -3/4 and the y intercept is 2

How to graph: Knowing the y-intercept is 2, plot a point at (0,2) "x=0, y=2", and trace a point backwards from there using the slope until the x-axis is reached

Rise over run method

Now how to trace this starting from a single point y=2 and x=0, excuse my mouse writing:

You trace the pencil down -3 spaces, then go over +4 spaces, then trace a full line when have enough points.

x-2y=6

-2y=6-x

Divide by -2

y=-3+(1/2)x

Here you know the y intercept is -3 and the slope (rise over run) is (1/2)

Use the same method to graph this starting at y=-3 and x=0

Here starting at (0,-3), you would trace up one point (positive 1), then over 2, then repeating again until you have enough points to plot a long line for the graph.

Let me know if you need any other advice and good luck.
Oct 9th, 2015

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Oct 9th, 2015
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Oct 9th, 2015
Sep 25th, 2017
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