设x-y=a+3 ① 2x+y=5a②
①+②得:3x=6a+3
x=2a+1,代入①得:y=a-2
(1) 若x>y>0,即:2a+1>a-2>0得 a>2
(2) a取3,4,5,6,7,8,9,10