Answer:
Step-by-step explanation:
According to the condition, your terms are arranged as
5, 7 , -7 ,-5, 5, 7, -7, 5, -5,...................
So one loop will have 4 terms: 5, 7, -7. -5
Hence after 63 loops, the new loop has only 3 terms. That means the last loop will be 5, 7 ,-7. In other words, the 255th term will be -7