Bring ABC three-point coordinates into the parabolic equation and get a parabola:

y=x^2+4x+3

2

P is a point on a parabola, so when P is (-4, m), m=3.

Q is a point on a straight line, which intersects with the X axis to get the coordinates of point Q (4,0).

PC is parallel to OQ, and PC=OQ=4. PCQO is a parallelogram.

∠OPC=∠AQC

3、

Suppose the ordinate of n is h.

Then s δ AMN = 1/2 am h.

AM=3t

h=OC-sin∠AQCXt=3-3/5t

sδamn=4.5t( 1-0.2t)=-0.9t^2+4.5t

T=2.5 is the largest area, but considering

3t = < AQ，t = < CQ。

Let t=7/3, at this time, S=5.6.

If PQ divides MN vertically, there must be QN=QM.

QN=5 tons

QM=7-3t

At this time t= 1.

The coordinate of m at this time is (0,0 0) n at this time is (0.8,2.4).

PQ crosses the midpoint of MN (0.4, 1.2).

Get the straight line k=- 1/3.

y=- 1/3(x-4)

Substitution parabola

3x 2+ 13x+5 = 0。

P (-0.4438+05538+0848 24438+06， 1)。 48638.86668666667

Or (-3.99438+0538+04092,2). 39936.88868886666