Study Guide and Review
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Use the formula for the nth term of an arithmetic sequence.
a_9=- 22
Explicit equations for the nth term of an arithmetic sequence follow a certain format.
a_n= a_1+( n-1) d
In this form, a_1 is the first term in the sequence, d is the common difference, and n is the position of the desired term in the sequence. We are given that a_1= 10 and d= - 4, so we can substitute these values to write the equation.
Distribute (- 4)
Remove parentheses
Add terms
To find the value of the 9th term, we substitute n= 9 into this equation and solve for a_9.
The 9th term in the sequence is - 22.