The graph shows a first quadrant quadrilateral region with the two coordinate axes as two edges of the quadrilateral
and the two constraint equations determining the other two edges. The region is colored in a linear gradient so that
colors can show the values of the objective function. Three equally spaced color stops are used in the gradient.
This configuration imposes some restrictions on the constraint equations, though:

- The lines determined by the constraint equations
*must* intersect, and the point of intersection
*must* be in the first quadrant, *not* on either of the coordinate axes.
- At least one of the two lines determined by the constraint equations
*must* intersect the positive \(x\)-axis, and similarly at least one of
the two lines *must* intersect the positive \(y\)-axis.

With these restrictions, the vertices of the quadrilateral are the following four distinct points:
the origin, the \(y\)-intercept point closest to the
origin, the point of intersection of the two constraint equation lines, and the \(x\)-intercept point closest to the
origin. If the restrictions are not met, a message appears indicating "Invalid constraints."