I need help, arithmetic sequences always mess me up
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Answer:
[tex]a_{45}=399[/tex] is the required term.
Step-by-step explanation:
We have been given an arithmetic sequence where we have a common difference which is:[tex]d=a_2-a_1[/tex]
[tex]d=12-3=9[/tex]
We will use the formula to find the required term:
[tex]a_n=a+(n-1)d[/tex]
where, a is first term which is 3 and d is the common difference which is 9
and n =45 which we require to find.
[tex]a_{45}=3+(45-1)(9)[/tex]
[tex]a_{45}=3+396[/tex]
[tex]a_{45}=399[/tex].
Answer:
Missing term of the sequence is 399.
Step-by-step explanation:
In the given table we will try to find the sequence in terms of y and x parameters.
Since y = 3, 12, 21, 30,......... it's an arithmetic progression then we can represent nth term of this sequence as y = a + (x-1)d where a = first term, x = number of terms and d = common difference.
y = 3 + (x-1)×d = 3 + (x-1)×9 = 3 + 9x -9 = (9x - 6)
Now we have to find the term x = 45 ( 45th term)
By putting the value of x = 45 in the equation we will find the value of y.
y = 9×45 - 6 = 405 -6 = 399