Hi i need to know if this is a function...

17 in long 1.3 ft wide and 8in high what is the volume

For the sequence [tex]a_{n} = 2n/(n+1)[/tex], what is the value of [tex]a_{10}[/tex]

The first term of a sequence is -12. the recursive formula for the sequence is an = an-1 + 9. what are the next 3 terms in the sequence? a) -3, -15, -27 b) -3, 6, 15 c) -3, -6, -3 d) -3, -6, 3