Answer
$a_n=-0.7-0.2(n-1)$
$a_{10} = -2.5$
Work Step by Step
RECALL:
The $n^{th}$ term $a_n$ of an arithmetic sequence can be found using the formula:
$a_n = a + d(n-1)$
where
$a$ = first term
$d$ = common difference
$n$ = term number
The given arithmetic sequence has $a=-0.7$ and $d=-0.2$.
This means that the $n^{th}$ term of the sequence is given by the formula:
$a_n = -0.7 + (-0.2)(n-1)
\\a_n=-0.7-0.2(n-1)$
Thus, the 10th term of the sequence is:
$a_{10} = -0.7-0.2(10-1)
\\a_{10}=-0.7-0.2(9)
\\a_{10} = -0.7-1.8
\\a_{10} = -2.5$
