What is the simplified form of ( (x+4)(x-6)-(x-4)(x+6) )?
Answer and explanation
Correct answer: \(-4x\)
\((x+4)(x-6)=x^2-2x-24\), while \((x-4)(x+6)=x^2+2x-24\). On subtracting the second expression, \(x^2-2x-24-(x^2+2x-24)=-4x\). Therefore, the correct answer is \(-4x\). The option \(4x\) results from an incorrect sign while subtracting the bracketed expression. Exam tip: when subtracting a whole expression, change the sign of every term inside its bracket.
Frequently asked questions
What is the correct answer to this question?
\(-4x\)
Why is this the correct answer?
\((x+4)(x-6)=x^2-2x-24\), while \((x-4)(x+6)=x^2+2x-24\). On subtracting the second expression, \(x^2-2x-24-(x^2+2x-24)=-4x\). Therefore, the correct answer is \(-4x\). The option \(4x\) results from an incorrect sign while subtracting the bracketed expression. Exam tip: when subtracting a whole expression, change the sign of every term inside its bracket.
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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