Write an explicit formula for the sequence -4, 1, 6,

an= -4+ 5(n+1)
an= -4+ 5(n-1)
an= -4+ (n-1)
an= -4+ 5n

This is an arithmetic sequence because each term is 5 more than the previous term, the defining characteristic of an arithmetic sequence which is called the common difference.  All arithmetic sequences can be expressed as:

a(n)=a+d(n-1), a=1st term, d=common difference, n=term number, in this case a=-4 and d=5 so

a(n)=-4+5(n-1)

The answer simplified would be. -6300x