Can anyone help me with these two questions please?

(1) Answers

That top one is a geometric sequence because it has a common ratio.  The common ratio is just a constant multiple that exists between any term and the previous one.  In this case it is: -44/88=22/-44=r=-1/2 Any geometric sequence can be expressed as: a(n)=ar^(n-1), a=initial term, r=common ratio, n=term number, in this case: a=88 and d=-1/2 so a(n)=88(-1/2)^(n-1) so the fourth and fifth terms are: a(4)=88(-1/2)^(3)=-11, a(5)=88(-1/2)^4=5.5 ..... Again, this is a geometric sequence because there is a common ratio, r of: 16.8/42=6.72/16.8=r=0.4 or if you prefer 4/10, and a=42 so the rule is: a(n)=42(4/10)^(n-1) so the fourth term is: a(4)=42(4/10)^3=2.688

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