Let X=0 and Y=4.

Therefore, the coordinate of the intersection of the linear function image and the y axis is (0,4).

The straight line X= 1 intersects the x axis at point b (1, 0).

X=4, and the X axis intersects C (4,0).

The quadrilateral ABCD is a convex quadrilateral.

As shown in the figure, the function image should be between two straight lines (find m in the critical relationship respectively).

So- 1

2.？ The straight line y=4m+4 intersects the X axis at point E, that is, mx+4=0? (y=0)，？ X=-4/m, then the coordinate of point E is (-4/m, 0).

Because ED/EA=4/7, EC/EB=4/7. (The corresponding sides of similar triangles are proportional)

(EB-EC)/EB=(7-4)/7=3/7。

[? (-4/m- 1-(-4/m-4)]/(-4/m- 1)= 3/7。

3*7=3(-4/m- 1)。

-4/m- 1=7。

-4/m=6，

m=-3/2。

∴y=(-3/2)x+4.

3x+2y-8=0？ -that is, to find the analytical formula of linear function.