1 year ago
Rearrange letters so as to group duplicates together:
I LLL OO PP

1 I
3 L's
2 O's
2 P's
8 letters in total

Permutations: 8! / (1! * 3! * 2! * 2!) = 1680

4.

(x + 2y)^8 = ∑ [k = 0 to 8] C(8,3) x^(8−k) (2y)^k

Since we start with k = 0, then 4th terms means k = 3

C(8,3) x^(8−3) (2y)^3
= 56 x^5 * 8y^3
= 448 x^5 y^3
TAG:
Best Answer
Other Answers