13, start with 24, right? 24 plus 6 is 30. 30 minus 12 is 18. 18 minus 5 is 13.
Answer:
aₙ = aₙ₋₁ + aₙ₋₂
where:
a₁ = 6
a₂= 1.
Step-by-step explanation:
We have the sequence:
6, 1, 7, 8, 15, 23, ...
Is easy to see that this sequence works as follows:
You take 2 consecutive numbers, and the next number is the sum of these two.
Then we have:
6 + 1 = 7
1 + 7 = 8
7 + 8 = 15
8 + 15 = 23
Then the n-th term is equal to the sum of the (n - 1) term and the (n - 2) term.
This is written as:
aₙ = aₙ₋₁ + aₙ₋₂
Because in the recursive rule needs two previous terms, we need to specify the two first terms of the sequence.
Then we need to write also:
a₁ = 6
a₂= 1.
I like the substitution method. Which is when you make one equation equal only x or y and plug it into the other equation)
There is also the graphing method. If you graphed it, it might not be quite as accurate (at least on hand, on computer you would be pretty exact)
Then there is the elimination method. You multiply one of the equations by a coefficient so that you can eliminate x or y from the equation.
