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Which of the following expressions can be factorised using the identity for the difference of squares, \(a^2-b^2=(a-b)(a+b)\)?
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Answer and explanation
Correct answer: \(y^2-49\)
\(y^2-49=y^2-7^2\) is a difference of two perfect squares, so it factorises as \((y-7)(y+7)\). \(y^2+49\) is a sum of squares. In exams, check for perfect squares separated by a minus sign.
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What is the correct answer to this question?
\(y^2-49\)
Why is this the correct answer?
\(y^2-49=y^2-7^2\) is a difference of two perfect squares, so it factorises as \((y-7)(y+7)\). \(y^2+49\) is a sum of squares. In exams, check for perfect squares 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: Factorisation.
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