Find an equation for the nth term of the arithmetic sequence.
-17, -13, -9, -5, ...
hellppppp pleaseee

Question

Find an equation for the nth term of the arithmetic sequence.
-17, -13, -9, -5, ... 
hellppppp pleaseee

.sam. · Answer

First thing you have to know is whether it is A.P or G.P

anonymous · Answer

a.p or g.p?

.sam. · Answer

Arithmetic progression
Geometric progression

anonymous · Answer

Arithmetic

.sam. · Answer

From here you can tell that it's AP, yes

anonymous · Answer

find the difference between each number (i.e. 4), set up initial progression 4n+b
then work out what b is by calculation 
-17 = 4n+b
b=-21
so your progression is 4n-21

.sam. · Answer

the common difference is
d=-13-(-17)=4

anonymous · Answer

ohhh okay thank you. could you help me with another one?

anonymous · Answer

yeah

.sam. · Answer

Then follow what @epicfail said

anonymous · Answer

so I got 17 + 4(n - 1)

anonymous · Answer

Write the sum using summation notation, assuming the suggested pattern continues.
2 - 6 + 18 - 54 + ...