No need to answer to all but I've been having trouble all day. Pls & thank you
1) What is the d value of the following sequence? 3, -6, -15, -24, -33,…
2)Find the 3rd term of an arithmetic sequence with t5 = 3 and t7 = 7.
3)Find the four arithmetic means between 12 and -13.
4) Find S12 for 1 + 6 + 11 + 16 +…

Question

No need to answer to all but I've been having trouble all day. Pls & thank you 
1) What is the d value of the following sequence? 3, -6, -15, -24, -33,… 
2)Find the 3rd term of an arithmetic sequence with t5 = 3 and t7 = 7.  
3)Find the four arithmetic means between 12 and -13.
4) Find S12 for 1 + 6 + 11 + 16 +…

solomonzelman · Answer

1)    -9
2)    -1
3)      7,  2,  -3,  -8
4)      56
@lavillainy.   Here it is.