Question

write an explicit formula for the sequence 10,9.5,9,8.5,8 then find a8

Answer 1

an=a1+d(n-1)
a1=first term
d=common differnce
n=which term

minusing 0.5 each time
first term is 10

an=10-0.5(n-1)
8th term
a8=10-0.5(8-1)
a8=10-0.5(7)
a8=10-3.5
a8=6.5

the 8th term or a8 is 6.5

Answer 2

$a_{n} = a_{1} + (n-1)d$
$a_8 = 10 + (8-1)(-0.5) a_8 = 10 + (7)(-0.5) a_8 = 10 + -3.5 a_8 = 6.5$