Answer:
39 is the 13th term
Explanation:
Okay so essentially the
is just a substitute for x.
See how in the equation they put n into the x spot:
They changed the variable names:
Now we know what the n actually means, plus when they ask about the terms youre trying to find it's based off of that n:
When they say, 13 term, they mean
which would be the 13th answer in the series. So the first term would be based off of
So whatever number is in the n position by a is what you'll be plugging into the x spot.
These are all the answers leading up to the 13th term they asked for, and you can continue thus same equation with whatever number you can put into the n space.