The inequality *x* + 2 < 0 can also be thought of as asking "when is the line *y = x* + 2 below (less than) the line *y* = 0.
Since *y* = 0 is the *x*-axis, this example is looking for when the line *y = x* + 2 is below (less than) the *x*-axis.
The *x*-intercept occurs when *x* = -2, and the line *y = x *+ 2 is below *y *= 0 to the left of the point (-2,0). The solution is the *x*-values less than -2 (written * x* < -2).
A graphing calculator displays inequalities in this same manner. |