If \(n=-4\), what is the value of \(\frac{n^2+n}{2}\)?
Answer and explanation
Correct answer: 6
Substituting \(n=-4\), we get \(n^2=(-4)^2=16\). Hence, \(\frac{n^2+n}{2}=\frac{16+(-4)}{2}=\frac{12}{2}=6\). Therefore, 6 is the correct answer. The distractor 8 results from wrongly ignoring the \(n=-4\) term in \(n^2+n\). Exam tip: always put a negative number in brackets before squaring it.
Frequently asked questions
What is the correct answer to this question?
6
Why is this the correct answer?
Substituting \(n=-4\), we get \(n^2=(-4)^2=16\). Hence, \(\frac{n^2+n}{2}=\frac{16+(-4)}{2}=\frac{12}{2}=6\). Therefore, 6 is the correct answer. The distractor 8 results from wrongly ignoring the \(n=-4\) term in \(n^2+n\). Exam tip: always put a negative number in brackets before squaring it.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Algebraic expressions.
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