(1): when x is less than or equal to 8, p moves on BC, BP=X, and height AB=6, so Y=3X.

When x is greater than 8 and less than 18, p moves on AC, and based on CP, it is greater than 6*8/ 10=4.8 (equal area formula). AP=BC+AC-X= 18-X, so Y=2.4*( 18-X).

When x is greater than or equal to 18 and less than or equal to 24, it does not form a triangle, and the area is 0 Y=0.

(2):Sabc=24。 Then Y=6. Substitute Y=6 into Y=3X and y = 2.4 (1) to get X=2 and X= 15.5.