Which of the following expressions can be directly identified as a difference of two perfect squares?
Answer and explanation
Correct answer: \(81m^4-16n^6\)
Since \(81m^4=(9m^2)^2\) and \(16n^6=(4n^3)^2\), option A has the form \(a^2-b^2\) and factors as \((9m^2-4n^3)(9m^2+4n^3)\). Option B is a sum, not a difference. Exam tip: check for two square terms separated by a minus sign.
Frequently asked questions
What is the correct answer to this question?
\(81m^4-16n^6\)
Why is this the correct answer?
Since \(81m^4=(9m^2)^2\) and \(16n^6=(4n^3)^2\), option A has the form \(a^2-b^2\) and factors as \((9m^2-4n^3)(9m^2+4n^3)\). Option B is a sum, not a difference. Exam tip: check for two square terms separated by a minus sign.
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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