Question

方程丨x-2y-3丨+丨x+y-1丨=1的整数解的个数是

Answer 1

因为x,y都为整数,那么丨x-2y-3丨喝丨x+y-1丨都为整数,有丨x-2y-3丨=1,丨x+y-1丨=0或丨x-2y-3丨=0,丨x+y-1丨=1解得y=-1/3,x=7/3(舍）或y=-1,x=2