Equations describing a shaded region (inequalities)

[victoration1]

Homework Statement

Question 42 in particular.

Homework Equations

No idea.

The Attempt at a Solution

The graph depicts an inequality of sorts, like y >= x and y >= -x as well as y <= x and y <= -x. Beyond these basic deductions (which are probably wrong also), I've not a scintilla of clue what to do next.

 

[HallsofIvy]

Do you know how to distinguish equations of straight lines from equation of curves?