No., I think the book answer is correct
1 7
2 3
3 4 7-3 a3=a1-a2
4 -1 3-4 a4=a2-a3
5 5 4 -(-1) a5=a3-a4
The interesting question is what is the general solution? If you want to know the answer to that, you will have to send me a message telling me so. E2 + E - 1