Which expression is equal to (2(a+b)-a)?
Answer and explanation
Correct answer: \(a+2b\)
On expanding the bracket, \(2(a+b)-a=2a+2b-a\). Combining like terms gives \(2a-a=a\), so the expression equals \(a+2b\). The option \(2a+b\) does not simplify the \(a\)-terms correctly. Exam tip: while expanding brackets, multiply the outside coefficient by every term inside the bracket.
Frequently asked questions
What is the correct answer to this question?
\(a+2b\)
Why is this the correct answer?
On expanding the bracket, \(2(a+b)-a=2a+2b-a\). Combining like terms gives \(2a-a=a\), so the expression equals \(a+2b\). The option \(2a+b\) does not simplify the \(a\)-terms correctly. Exam tip: while expanding brackets, multiply the outside coefficient by every term inside the bracket.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Algebraic expressions.
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