If (a_n=2n^2+3n-4), what is the value of (a_{10}-a_7)?
Answer and explanation
Correct answer: 111
Given
\(a_n=2n^2+3n-4\). Thus,
\(a_{10}=2(10)^2+3(10)-4=226\) and
\(a_7=2(7)^2+3(7)-4=115\). Therefore,
\(a_{10}-a_7=226-115=111\). A value such as 118 can result from an error while evaluating the squared term. In an exam, calculate the two terms separately before subtracting.
Frequently asked questions
What is the correct answer to this question?
111
Why is this the correct answer?
Given
\(a_n=2n^2+3n-4\). Thus,
\(a_{10}=2(10)^2+3(10)-4=226\) and
\(a_7=2(7)^2+3(7)-4=115\). Therefore,
\(a_{10}-a_7=226-115=111\). A value such as 118 can result from an error while evaluating the squared term. In an exam, calculate the two terms separately before subtracting.
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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