I think the text book answer is incorrect here, but wanted to have someone else confirm if this was the case. Thanks in advance.
Q. Find U_{n}, the n^{th} term of sequence: -5, 0, 5, 10,...
Attempt: U_{n }= a + (n - 1)d => -5 + (n - 1)5 = -5 + 5n -5 = 5n - 10
Ans.: (From text book): U_{n }= 5n