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Which of the following expressions can be factorised using the identity for the difference of two squares, \(p^2-q^2=(p+q)(p-q)\)?
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Answer and explanation
Correct answer: \(9a^2-16b^2\)
\(9a^2-16b^2=(3a)^2-(4b)^2\), so it factorises as \((3a+4b)(3a-4b)\). Option D is a perfect square, \((3a-4b)^2\), not a difference of squares. Exam tip: identify the signs first.
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What is the correct answer to this question?
\(9a^2-16b^2\)
Why is this the correct answer?
\(9a^2-16b^2=(3a)^2-(4b)^2\), so it factorises as \((3a+4b)(3a-4b)\). Option D is a perfect square, \((3a-4b)^2\), not a difference of squares. Exam tip: identify the signs first.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Exploring Algebraic Identities. Topic: Factorisation.
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