The system of inequalities are
,
,
and
.
Graph:
\Graph the inequalities are
,
,
and
.

Observe the graph:
\The coordinates are
,
and
.
\ \
The equations are
and
.
Solve the equations.
\
(First equation)
(Substitute
)
(Add
to each side)
(Apply additve inverse property:
)
(Subtract
from each side)
(Apply additve inverse property:
)
(Divide each side by
)
(Cancel common terms) \ \
Find
.
(Second equation)
(Substitute
)
(Multiply)
(Subtract:
)
The vertices of the quadrilateral are
,
,
and
.
Graph of the inequalities are
,
,
and
is

The vertices of the quadrilateral are
,
,
and
.