Answer:
Tn= -2n +29
Explanation:
The terms decreases by 2 from the previous term. Hence they have a common difference of -2.
Tn= a +d(n-1), where a is the 1st term and d is the common difference.
When d= -2, a=27,
Tn= 27 -2(n-1)
Tn= 27 -2(n) -2(-1) (expand)
Tn= 27 -2n +2
Tn= -2n +29 (simplify)
Let's check!
When n=3,
T₃= -2(3) +29
T₃= 29 -6 (expand)
T₃= 23 (simplify)
✓ This is correct as the 3rd term in the sequence is 23.