Mathematics : Arithmetic Sequence
posted by Charmian on .
Consider the arithmetic sequence x+2, 18x, 14+x,...
a) Find the value of x.
b) Find the general term of the arithmetic sequence.

in general an = a1 + (n1)d
d = (18x)(x+2) = (14+x)(18x)
d = 16 2x = 4 +2x
so
4 x = 20 and x = 5
then d = 4 + 2x = 6
so
an = a1 + (n1)6
if the first term is x+2 = 7
then the sequence is
an = 7+(n1)6 
2,10,18,26

a1= 2
d=8
n=4
a5=2+(51)8
a5=2+32
a5=34