If (a=17) and (d=-4), what is the value of (a_8)?
Answer and explanation
Correct answer: -11
The nth term of an arithmetic progression is given by \(a_n=a+(n-1)d\). Therefore, \(a_8=17+(8-1)(-4)=17-28=-11\). Hence, option C is correct. A value such as \(-9\) can result from using the wrong term number or forgetting the \((n-1)\) factor. Exam tip: when \(d\) is negative, each successive term decreases.
Frequently asked questions
What is the correct answer to this question?
-11
Why is this the correct answer?
The nth term of an arithmetic progression is given by \(a_n=a+(n-1)d\). Therefore, \(a_8=17+(8-1)(-4)=17-28=-11\). Hence, option C is correct. A value such as \(-9\) can result from using the wrong term number or forgetting the \((n-1)\) factor. Exam tip: when \(d\) is negative, each successive term decreases.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Arithmetic Progression.
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