This problem involves a negative common difference, meaning the sequence is decreasing. Use the nth term formula: \(T_n = a + (n-1)d\). Given: a = 100, d = -7, n = 8. Substitution: \(T_8 = 100 + (8-1)(-7)\). Calculation: \(T_8 = 100 + 7 \times (-7) = 100 + (-49) = 100 - 49 = 51\). The 8th term is 51. Verification by listing: 100, 93, 86, 79, 72, 65, 58, 51. The 8th term is indeed 51 ✓. Notice how each term decreases by 7. Important note for ECZ exams: When d is negative, be careful with signs. Many students make errors like writing \(7 \times (-7) = 49\) instead of \(-49\). Take your time with negative numbers. This type of decreasing sequence appears in real-world contexts like depreciation of vehicle values, decreasing temperatures, countdown sequences, or diminishing resources.

Break down complex topics into smaller, manageable chunks for easier recall.

Zambia

• Joseph Soko – 101 pts

• Distance of A Straight Line
• Mid-point of A Line
• Equation of a Straight Line
• Parallel and Perpendicular Lines
• COMMUNICATION SYSTEMS