What is the middle term in ( (2a-b)^2 )?
Answer and explanation
Correct answer: \(-4ab\)
Using the identity \((x-y)^2=x^2-2xy+y^2\), the middle term is \(-2xy\). Here, \(x=2a\) and \(y=b\), so the middle term is \(-2\times 2a\times b=-4ab\). The option \(-2ab\) misses the coefficient 2 in \(2a\). Exam tip: always multiply the coefficients of both terms while finding the middle term.
Frequently asked questions
What is the correct answer to this question?
\(-4ab\)
Why is this the correct answer?
Using the identity \((x-y)^2=x^2-2xy+y^2\), the middle term is \(-2xy\). Here, \(x=2a\) and \(y=b\), so the middle term is \(-2\times 2a\times b=-4ab\). The option \(-2ab\) misses the coefficient 2 in \(2a\). Exam tip: always multiply the coefficients of both terms while finding 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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