If (a_n=4n^2+5n-6), what is the value of (a_3+a_5)?
Answer and explanation
Correct answer: 164
Given \(a_n=4n^2+5n-6\), \(a_3=4(3)^2+5(3)-6=45\) and \(a_5=4(5)^2+5(5)-6=119\). Therefore, \(a_3+a_5=45+119=164\). A nearby value such as 162 can result from a small addition or multiplication error. Exam tip: substitute each value of \(n\) separately before adding the terms.
Frequently asked questions
What is the correct answer to this question?
164
Why is this the correct answer?
Given \(a_n=4n^2+5n-6\), \(a_3=4(3)^2+5(3)-6=45\) and \(a_5=4(5)^2+5(5)-6=119\). Therefore, \(a_3+a_5=45+119=164\). A nearby value such as 162 can result from a small addition or multiplication error. Exam tip: substitute each value of \(n\) separately before adding the terms.
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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