SOLUTION: please help: -7x+3y<-18 Graph linear inequality. (please show steps)

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Question 161962: please help: -7x+3y<-18 Graph linear inequality. (please show steps)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
In order to graph -7x%2B3y%3C-18, we need to graph the equation -7x%2B3y=-18 (just replace the inequality sign with an equal sign).
So lets graph the line -7x%2B3y=-18 (note: let me know if you need help with graphing equations)
+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+%287%2F3%29x-6%29+ graph of -7x%2B3y=-18
Now lets pick a test point, say (0,0). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality -7x%2B3y%3C-18 with the test point

Substitute (0,0) into the inequality
-7%280%29%2B3%280%29%3C-18 Plug in x=0 and y=0
0%3C-18 Simplify



Since this inequality is not true, we do not shade the entire region that contains (0,0). So this means we shade the region that is on the opposite side of the line. In other words, we shade the ENTIRE region below the line like this:

Graph of -7x%2B3y%3C-18 with the boundary (which is the line -7x%2B3y=-18 in red) and the shaded region (in green)
(note: since the inequality contains a less-than sign, this means the boundary is excluded. This means the solid red line is really a dashed line)