Which of the following terms does not appear in the expansion of \((a-b)^3\)?
Answer and explanation
Correct answer: \(3ab^2\)
\((a-b)^3=a^3-3a^2b+3ab^2-b^3\), so \(3ab^2\) does appear with a positive sign. Hence none of the listed terms is absent; the options are flawed. Exam tip: for a cube of a difference, signs follow +, −, +, −.
Frequently asked questions
What is the correct answer to this question?
\(3ab^2\)
Why is this the correct answer?
\((a-b)^3=a^3-3a^2b+3ab^2-b^3\), so \(3ab^2\) does appear with a positive sign. Hence none of the listed terms is absent; the options are flawed. Exam tip: for a cube of a difference, signs follow +, −, +, −.
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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