Find 26th term in the arithmetic sequence: -15,-35,-55,-75,...
Mathematics · Middle School · Tue Nov 03 2020
Answered on
Given the arithmetic sequence:
-15,-35,-55,-75
Determine the 26th term.
n=26
Formula for arithmetic sequence:
A(n) = A1 + (n-1)d
Solution:
We must first find the common difference d, in order to solve for the 26th term. The common difference can be found by subtracting the first term with the second term.
A1 = -15
A2 = -35
Common Difference = -35 - (-15)
Common Difference = -35 + 15
Common Difference = -20
Substitute the given values to the formula for arithmetic sequence:
A(26)= -15 + (26 - 1) -20
A(26)= -15 + (25)-20
A(26)= -15 -500
A(26)= -515
Final answer:
The 26th term is -515.