JAMB - Mathematics (2022 - No. 29)
Evaluate \(^{n^2 + 1}\)C\(_{n+5}\) if n = 3
55
45
35
25
Explicaţie
\(^{3^2 + 1}\)C\(_{3+5}\)
\(^{9 + 1}\)C\(_{3+5}\)
\(^{10}\)C\(_{8}\) = \(\frac{10!}{8! 2!}\)
\(\frac{10 * 9 * 8!}{8! 2!}\) = \(\frac{10 * 9}{2}\)
= 45