First, we observe that
and
so that
is in the first quadrant. Any line
that slices this region into two pieces must then have a slope between
and
(which is the slope of the tangent line to the curve through the origin).
The parabola and line meet at the origin, and again when
with
for
.
Now, the total area of
is
so that half the area is 16/3.
The area of the left piece (containing the origin) is
Solve for
.