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Which of the following expressions can be written using the identity for the difference of two cubes?
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Answer and explanation
Correct answer: a^3-b^3
A difference of two cubes has the form \(a^3-b^3\) and factorises as \((a-b)(a^2+ab+b^2)\). \(a^3+b^3\) is a sum of cubes, so it uses a different identity. Exam tip: for a difference, the first binomial is \(a-b\).
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What is the correct answer to this question?
a^3-b^3
Why is this the correct answer?
A difference of two cubes has the form \(a^3-b^3\) and factorises as \((a-b)(a^2+ab+b^2)\). \(a^3+b^3\) is a sum of cubes, so it uses a different identity. Exam tip: for a difference, the first binomial is \(a-b\).
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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