Question 5
The diagram shows nine circles joined by five solid lines and two dashed lines. Fill in the circles using each of the numbers $1,2,3,4,5,6,7,8$ and $9$ exactly once, such that the number in the middle circle of a solid line is equal to the sum of the numbers in the other circles on the line, and the number in the middle circle of a dashed line is equal to the difference of the numbers in the other circles on the line. Find all solutions.
