Question

permutations: can someone explain why you multiply in step 2?
nP5 - nP4
1. = n(n-1)(n-2)(n-3)(n-4) - n(n-1)(n-2)(n-3)
2. = n(n-1)(n-2)(n-3) * [(n-4) - 1]
3. = n(n-1)(n-2)(n-3) * [n-5]

Answer 1

Take n(n-1)(n-2)(n-3) common in both sides

Answer 2

sorry what does that mean?

Answer 3

\(\huge\bf\rlap{\color{green}{hi~kiddos}}{\color{orange}{\;~}}\)

Answer 4

Factor out n(n-1)(n-2)(n-3)

Answer 5

Thanks! I forgot all about factoring