This question is confusing me a bit:
Explain why a point on the boundary line cannot be used as a test point when graphing a linear inequality in two variables. Provide an example.

Question

This question is confusing me a bit: 
Explain why a point on the boundary line cannot be used as a test point when graphing a linear inequality in two variables. Provide an example.

amistre64 · Answer

in generalm if you are standing in the middle of the road, which side of the road are you standing on?

the solution set of an inequality is an area on one side of a line or another; that can either include the line or not.

which side of the line will you pick for a solution area if you are standing on the line itself?

amistre64 · Answer

x^2 + y^2 <= 16

the boundary line is a circle; and we already know by the rule given that the line itself is included (or excluded).  By finding a point on the circle, how are you able to determine if the solution set includes the inside of the circle or the outside of the circle?  assuming of course that we cant determine it so easily from looking at the setup

directrix · Answer

Consider the  line y = x.


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