Write in terms of factorials. `5 xx 6 xx 7 xx 8 xx 9 xx 10`

Write in terms of factorials. 6 xx 7 xx 8 xx 9

Write in terms of factorials. 3 xx 6 xx 9 xx 12 xx 15

Write in terms of factorials. 5 xx 10 xx 15 xx 20

Find the sum 1 xx 3 xx 5 + 3 xx 5 xx 7 + 5 xx 7 xx 9 + ……. + (2n - 1) ( 2n + 1) ( 2n + 3)

Find S_n of the following arithmatical geometric sequence. 2 xx 1 , 4 xx 3 , 6 xx 9 , 8 xx 27 , 10 xx 81 …..