Which of the following expressions can be factorised directly using the identity \(a^2-b^2=(a-b)(a+b)\)?
Answer and explanation
Correct answer: \(9a^2-16b^2\)
\(9a^2-16b^2=(3a)^2-(4b)^2\), so it is a difference of squares and factors as \((3a-4b)(3a+4b)\). Option C is a perfect square. Exam tip: first identify the two squared terms.
Frequently asked questions
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 is a difference of squares and factors as \((3a-4b)(3a+4b)\). Option C is a perfect square. Exam tip: first identify the two squared terms.
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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