# Need help graphing the equation

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• Feb 13th 2013, 02:01 PM
yellowreconrider
Need help graphing the equation
-9x+2y=-18

My points are -9, (?)
-18, -90

what is the ? please help me understand
• Feb 14th 2013, 01:04 AM
BobP
Re: Need help graphing the equation
Graphing the equation is easy. Usually, with a straight line, the best method is to find out where the line crosses the x and y axes.
For all points on the x-axis, y=0. So, put y=0 into your equation and you find that x=2, so the line passes through the point (2,0).
Similarly to find out where it crosses the y-axis put x=0. That shows that the line passes through the point (0.-9).
Plot those two points and draw in the line that passes through them.

As to the numbers at the end, I assume that they should be written as (-9,?), (-18,-90) and are the co-ordinates of two points on the line, (though why they are significant I don't know). If that happens to be the case, simply substitute x=-9 into the equation to calculate the value of ? .