So A(-m, 0), B(2m, 0)

(2) Connect OE

D is the midpoint of OC, so Scde=Sode, Scdb=Sodb.

So Sobe=Scbe, Sobe=2Soae.

So Sceb:Saeb=2:3, ce:ae=2:3.

(3) Coordinates of point C (m, 2m^2)

SCED = SOED = 1.6, SCOE = 3.2, SAOC = 8 = m 3, and the solution is m=2.

Parabola y =-x 2+2x+8

A coordinate (-2,0), B coordinate (4,0) and C coordinate (2,8).

E coordinate (0.4,4.8), straight line be y=(-4/3)x+( 16/3).