8. As shown in the figure, there are two points A and B on the image of linear function y= 1/2X+2, the abscissa of point A is 2, and the abscissa of point B is a (0

A.s 1 & gt； S2 b . s 1 = S2 c . s 1 & lt； S2 D. can't be sure

It is suggested that the area of triangle AOC is easy to find, and it is S 1= 1, while the area of triangle BOD can be represented by a as S2 =- 1/4a 2+a, and then-1/4 (a-2) 2+65438 can be obtained by the formula. A<4, while a≠2 shows-1/4 (A-2) 2+ 1