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Which of the following identities has the cross term \(-2pq\) in its expansion?
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Answer and explanation
Correct answer: \((p-q)^2=p^2-2pq+q^2\)
In \((p-q)^2\), the product of the terms is \(p(-q)=-pq\), so the cross term is \(2\times(-pq)=-2pq\). In \((p+q)^2\), it is \(+2pq\). Exam tip: always check the sign of the middle term.
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What is the correct answer to this question?
\((p-q)^2=p^2-2pq+q^2\)
Why is this the correct answer?
In \((p-q)^2\), the product of the terms is \(p(-q)=-pq\), so the cross term is \(2\times(-pq)=-2pq\). In \((p+q)^2\), it is \(+2pq\). Exam tip: always check the sign of the middle term.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Exploring Algebraic Identities. Topic: Algebraic identities.
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