Determine whether the series -5 + 25 - 125 + ... is convergent or divergent.

This is a geometric series with first term −5 and common ratio 25 ÷ (−5) = −5. An infinite geometric series converges only when the absolute value of its common ratio is less than 1; here |−5| = 5, so the terms do not approach zero and the series is divergent.

AI-written and checked against the verified answer.