A sequence has (a_n=3n^2-7n+6). What is the difference between (a_2) and (a_9)?
Answer and explanation
Correct answer: 182
Given \(a_n=3n^2-7n+6\), \(a_2=3(2)^2-7(2)+6=12-14+6=4\), while \(a_9=3(9)^2-7(9)+6=243-63+6=186\). Therefore, the difference is \(186-4=182\). A value such as 180 can result from a small calculation or subtraction error. Exam tip: substitute each value of \(n\) separately before finding the difference.
Frequently asked questions
What is the correct answer to this question?
182
Why is this the correct answer?
Given \(a_n=3n^2-7n+6\), \(a_2=3(2)^2-7(2)+6=12-14+6=4\), while \(a_9=3(9)^2-7(9)+6=243-63+6=186\). Therefore, the difference is \(186-4=182\). A value such as 180 can result from a small calculation or subtraction error. Exam tip: substitute each value of \(n\) separately before finding the difference.
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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