if {an} is an arithmetic where a1=-23 and the common difference is 6, find a79.
A. 445
B. 491
C. 439
D. 451
please help
per the usual definition,
a79 = a1 + 78d
so now just plug in your numbers
answer is 445. a1+78(6)=445. :)
To find the value of the 79th term of the arithmetic sequence, we can use the formula:
an = a1 + (n-1)d
where:
an = value of the nth term
a1 = first term
n = term number
d = common difference
Given:
a1 = -23 (first term)
d = 6 (common difference)
n = 79 (term number)
Using the formula, we substitute the given values:
a79 = -23 + (79-1) * 6
Simplifying the equation:
a79 = -23 + 78 * 6
a79 = -23 + 468
a79 = 445
Therefore, the value of a79 is 445.
So, the correct option is A. 445.
To find the value of a79 in an arithmetic sequence with a first term of a1 = -23 and a common difference of 6, you can use the formula for the nth term of an arithmetic sequence:
an = a1 + (n - 1)d,
where an is the nth term, a1 is the first term, n is the term number, and d is the common difference.
In this case, we want to find a79, so n = 79, a1 = -23, and d = 6.
Plugging those values into the formula, we get:
a79 = -23 + (79 - 1)6.
Simplifying the expression inside the parentheses:
a79 = -23 + 78 * 6.
Now we can calculate the value:
a79 = -23 + 468.
Finally:
a79 = 445.
Therefore, the answer is A. 445.