Which expression is obtained after simplifying (2x-3(4-x))?
Answer and explanation
Correct answer: \(5x-12\)
On opening the bracket, \(-3(4-x)=-12+3x\), because \(-3\) multiplies both 4 and \(-x\). Therefore, \(2x-3(4-x)=2x-12+3x=5x-12\). In \(5x+12\), the sign of the constant term is incorrect. Exam tip: when multiplying a bracket by a negative number, check the sign of every term.
Frequently asked questions
What is the correct answer to this question?
\(5x-12\)
Why is this the correct answer?
On opening the bracket, \(-3(4-x)=-12+3x\), because \(-3\) multiplies both 4 and \(-x\). Therefore, \(2x-3(4-x)=2x-12+3x=5x-12\). In \(5x+12\), the sign of the constant term is incorrect. Exam tip: when multiplying a bracket by a negative number, check the sign of every term.
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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