What is the recursive rule for the sequence?

−7.4, −21.2, −35, −48.8, −62.6, ...

an=an+1+13.8 , where a1=−7.4

an=an+1−13.8 , where a1=−7.4

an=an−1+13.8 , where a1=−7.4

an=an−1−13.8 , where a1=−7.4

Looks like the difference between terms is -48.8 - (-35) = -48.8 + 35 = -13.8

So.......

a_{n} = a_{n-1} - 13.8 , where a_{1} = - 7.4

[ Remember that a_{n} is the term after a_{n-1} ]