Question 481369: Please help me solve this problem, thank you.
Which term of the arithmetic progression -7,-5,-3 . . . is 65?
Answer by Maths68(1474)   (Show Source):
You can put this solution on YOUR website! Tn=a+(n-1)d
T=term
n=Number of term
a=first term
d=Common difference
In this particular series
a=-7,
d=-5-(-7)=-5+7=2
Tn=65
Tn=a+(n-1)d
65=-7+(n-1)2
65=-7+2n-2
65=-9+2n
65-9=2n
54=2n
54/2=n
27=n
n=27
65 is the27 term of the series -7,-5,-3,.......65
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