If an is a5
and
an-1 is a4
then using your recursive formula for an arithmetic sequence
an=an-1 +d
then
a5=a4+d
now, a4 =6 and common difference "d" is d=-11
hence
a5=6 -11
6-11= -5
any questions?
So x times y=3030
x and y=unknown
find the factors (factors of 6=2 and 3)
3030=2,3,5,101 so
two multiplication is
2 times 1515
3 times 1010
5 times 606
30 times 101
202 times 15
303 times 10
505 times 6
7.24-4.002=3.238
It is 3.238 meters longer than higher