Factorise (3a+3b+xa+xb).
Answer and explanation
Correct answer: \((3+x)(a+b)\)
Group the terms: \(3a+3b+xa+xb=3(a+b)+x(a+b)\). The common factor is \((a+b)\), so the factorised form is \((a+b)(3+x)=(3+x)(a+b)\). In option B, using \(a-b\) would change the signs of the terms containing \(b\). Exam tip: for a four-term expression, group two terms at a time and look for a common bracket.
Frequently asked questions
What is the correct answer to this question?
\((3+x)(a+b)\)
Why is this the correct answer?
Group the terms: \(3a+3b+xa+xb=3(a+b)+x(a+b)\). The common factor is \((a+b)\), so the factorised form is \((a+b)(3+x)=(3+x)(a+b)\). In option B, using \(a-b\) would change the signs of the terms containing \(b\). Exam tip: for a four-term expression, group two terms at a time and look for a common bracket.
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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