Question

1)What are the first four terms of the sequence represented by the expression n(n-1)-5

Answer 1

`a_n=n(n-1)-5 \\ \\ a_1=1(1-1)-5=1 * 0-5=0-5=-5 \\ a_2=2(2-1)-5=2 * 1-5=2-5=-3 \\ a_3=3(3-1)-5=3 * 2-5=6-5=1 \\ a_4=4(4-1)-5=4 * 3-5=12-5=7`

The first four terms are -5, -3, 1 and 7.