How do you graph the system of linear inequalities #2x+1>=y# and #x<5# and #y<x+2#?

1 Answer
Jun 25, 2017

Draw solid or dashed lines corresponding to equations, then test the origin, #(0,0)#, to shade. Where all three overlap is the final answer.

Explanation:

One way to graph a system of linear equations like this is to actually start by drawing them as if they were equalities first.

The inequality #2x+1 >= y# becomes #y=2x+1# When you graph that, you get
![Desmos.com and MS Paint](useruploads.socratic.org)

Testing the point #(0,0)#, you see that it's true that #1 >= 0#, so shade that side. Because the inequality is "less then or equal to", you draw a solid (not dashed) line.
![Desmos.com and MS Paint](useruploads.socratic.org)

Again, assume #x < 5# is really just #x=5#. This gives:
![Desmos.com and MS Paint](useruploads.socratic.org)

This time, the graph is dashed because you were given #x < 5#. Testing the point #(0,0)#, it is true that #x=0# is less than #5#, so we shade to the left.

Finally, pretending to graph #y < x+2# gives the line. We must used a dashed line and shade wherever the inequality is true. At the point, #(0,0)#, the inequality is false, which means we must shade the other side.
![Desmos.com and MS Paint](useruploads.socratic.org)

Finally, if we are to find out where ALL THREE inequality are true, you simply look for the solution where ALL THREE shaded parts overlap. That occurs here:
![Desmos.com and MS Paint](useruploads.socratic.org)