Find The Next Four Terms Of The Arithmetic Sequence 21,15,9,
Find the next four terms of the arithmetic sequence 21,15,9
Answer:
The next four terms are: 3, -3, -9, -15.
Step-by-step explanation:
The first 3 terms of the sequence: 21, 15, 9 (decreasing sequence)
a₁ = 21
a₂ = 15
a₃ = 9
Find the common difference (d):
a₂ - a₁ = a₃ - a₂
15 - 21 = 9 - 15
-6 = -6
d = -6
Find the next four terms a₄, a₅, a₆, a₇:
a₄ = a₃ + d
a₄ = 9 + (-6)
a₄ = 3
a₅ = 3 + (-6)
a₅ = -3
a₆ = -3 + (-6)
a₆ = -9
a₇ = -9 + (-6)
a₇ = -15
The next four terms are: 3, -3, -9, -15.
The sequence: 21, 15, 9, 3, -3, -9, -15.
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