Question 77595
x<1-y
y<-x+1
{{{graph(400,300,-10,10,-10,10,-x+1)}}}
That is the graph of the EQUALITY.
y<-x+1 is above or below it.
Pick any point that is not on the line, like (0,5)
That is your "test point".
Substitute the x,y values into the INEQUALITY:
5<-0+1
5<1
That is false.
So the half-plane containing that test point is NOT
the graph of the INEQUALITY.  The other half plane
IS the solution.
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If you had selected the test point (3,-10)
you would have substituted and gotten:
-10<-3+1
-10<-2
That is true
So the half-plane containing that test point IS
the graph of the INEQUALITY.
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Hope this helps.
Cheers,
Stan H.