Answer:
-625
Step-by-step explanation:
1. the formula is:
[tex]a_n=a_1+d*(n-1);[/tex]
where n - the number of the required term, d - the step between two neighbor terms, a₁ - the first term of the given sequence.
2. according to the formula above:
[tex]a_{51}=25-13*(51-1)=25-650=-625.[/tex]
