If (a_n=6^n-3n), what is the value of (a_3)?
Answer and explanation
Correct answer: 207
Substitute \(n=3\) in the given rule: \(a_3=6^3-3(3)=216-9=207\). Therefore, 207 is the correct option. The value 213 would result from not subtracting the \(3n\) term, so it is incorrect. Exam tip: For a term of a sequence, substitute the value of \(n\) everywhere first, then evaluate powers and the remaining operations.
Frequently asked questions
What is the correct answer to this question?
207
Why is this the correct answer?
Substitute \(n=3\) in the given rule: \(a_3=6^3-3(3)=216-9=207\). Therefore, 207 is the correct option. The value 213 would result from not subtracting the \(3n\) term, so it is incorrect. Exam tip: For a term of a sequence, substitute the value of \(n\) everywhere first, then evaluate powers and the remaining operations.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Explicit or general rule.
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