What will be the value of ( (m+3)(m-3) )?
Answer and explanation
Correct answer: \(m^2-9\)
This matches the identity \((a+b)(a-b)=a^2-b^2\). Taking \(a=m\) and \(b=3\), we get \((m+3)(m-3)=m^2-3^2=m^2-9\). \(m^2+9\) is incorrect because the signs are opposite here, so the squared terms are subtracted. Exam tip: Whenever you see \((a+b)(a-b)\), use the difference-of-squares identity directly.
Frequently asked questions
What is the correct answer to this question?
\(m^2-9\)
Why is this the correct answer?
This matches the identity \((a+b)(a-b)=a^2-b^2\). Taking \(a=m\) and \(b=3\), we get \((m+3)(m-3)=m^2-3^2=m^2-9\). \(m^2+9\) is incorrect because the signs are opposite here, so the squared terms are subtracted. Exam tip: Whenever you see \((a+b)(a-b)\), use the difference-of-squares identity directly.
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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