b) The sequence seems to respond to this relation:
[tex]a_n=a_{n-1}-10_{}[/tex]a) The common difference is d=-10:
[tex]a_2-a_1=-6-4=-10[/tex]We can generalize the sequence also referring it to the first term:
[tex]\begin{gathered} a_1=4 \\ a_2=4-10=-6 \\ a_3=-6-10=4-10-10=4-2\cdot10=-16 \\ a_n=4-(n-1)\cdot10 \end{gathered}[/tex]We can apply this to calculate a9:
[tex]a_9=4-(9-1)\cdot10=4-8\cdot10=4-80=-76[/tex]c) The 9th term is -76.
