After simplifying (7(2x-5)-5(3x+4)), which polynomial is obtained?
Answer and explanation
Correct answer: \(-x-55\)
On expanding the brackets, \(7(2x-5)=14x-35\) and \(-5(3x+4)=-15x-20\). Therefore, \(14x-35-15x-20=-x-55\). Hence, the correct polynomial is \(-x-55\). In \(-x+55\), the sign of the constant term is incorrect. Exam tip: when a minus sign is multiplied with a bracket, change the sign of every term inside it.
Frequently asked questions
What is the correct answer to this question?
\(-x-55\)
Why is this the correct answer?
On expanding the brackets, \(7(2x-5)=14x-35\) and \(-5(3x+4)=-15x-20\). Therefore, \(14x-35-15x-20=-x-55\). Hence, the correct polynomial is \(-x-55\). In \(-x+55\), the sign of the constant term is incorrect. Exam tip: when a minus sign is multiplied with a bracket, change the sign of every term inside it.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear polynomials.
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