Rizhao property road construction bidding

Solution: (1) As shown in the figure, OE = 80m, OC = ED = 100m, AE = 60m, BC = 70m,

∴ OA = 20m，OB = 30m，

That is, the coordinates of A and B are (0,20) and (30,0) respectively.

Let the analytical formula of straight line AB be y=kx+b(k≠0), then

30k+b=0b=20，

Solution, k =? 23b=20，

Then the analytical formula of straight line AB is y =-23x+20;

(ii) (1) The coordinate of point p is P(x, y).

Point P is on the straight line AB, so the coordinate of point P can be expressed as (x, -23x+20).

∴pk= 100-x,ph=80-(-23x+20)=60+23x，

∴s=( 100-x)(60+23x)；

(2) by s = (100-x) (60+23x) =-23 (x-5) 2+180503,

Therefore, when x=5, the maximum rectangular area is: sMax = 180503 square meters.