The reason for this is the following：

From the folding,

Say it again,

(2) Let AE=3t,

AD=4t。

See DE=5t from Pythagorean Theorem.

From (1),

In,,

T= 1。

OC=8, AE=3, and the coordinate of point C is (0,8).

The coordinates of point E are (10,3),

Let the analytical formula of straight line CE be y=kx+b,

solve

The coordinate of point p is (16,0).

(3) There are two straight lines L satisfying the condition: y =-2x+ 12,

y=2x- 12 .

Let me sweat first. This does not need to be analyzed. The slope is constant, so are the absolute values of a and b. Aren't these two lines?