The (n)th term of a sequence is (a_n=3n^2-2n+5). Find (a_8).
Answer and explanation
Correct answer: 181
Given \(a_n=3n^2-2n+5\), substitute \(n=8\): \(a_8=3(8)^2-2(8)+5=3\times64-16+5=181\). Therefore, 181 is correct. A value such as 189 can result from an error while evaluating \(8^2\) or performing the subtraction. Exam tip: evaluate the power first, then multiply, subtract, and add.
Frequently asked questions
What is the correct answer to this question?
181
Why is this the correct answer?
Given \(a_n=3n^2-2n+5\), substitute \(n=8\): \(a_8=3(8)^2-2(8)+5=3\times64-16+5=181\). Therefore, 181 is correct. A value such as 189 can result from an error while evaluating \(8^2\) or performing the subtraction. Exam tip: evaluate the power first, then multiply, subtract, and add.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: nth term.
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