the formula for arithmetic sequence is given by:
an=a+(n-1)d
where:
an=nth term
a=first term
n=number of terms
thus our first term will be:
a1=8
a2=8+(2-1)(-6)=2
a3=8+(3-1)(-6)=-4
a4=8+(4-1)(-6)=-10
a5=8+(5-1)(-6)=-16
a5=-16
thus the sequence will be:
8,2,-4,-10,-16...