What is the simplified form of ( (x+5)(x-3)-(x-5)(x+3) )?
Answer and explanation
Correct answer: \(4x\)
Expanding the first product gives \((x+5)(x-3)=x^2+2x-15\). Similarly, \((x-5)(x+3)=x^2-2x-15\). Subtracting the second expression gives \(x^2+2x-15-(x^2-2x-15)=4x\). Hence, the correct answer is \(4x\). The option \(8x\) may result from handling the negative signs while subtracting incorrectly. Exam tip: when a minus sign precedes brackets, change the sign of every term inside the brackets.
Frequently asked questions
What is the correct answer to this question?
\(4x\)
Why is this the correct answer?
Expanding the first product gives \((x+5)(x-3)=x^2+2x-15\). Similarly, \((x-5)(x+3)=x^2-2x-15\). Subtracting the second expression gives \(x^2+2x-15-(x^2-2x-15)=4x\). Hence, the correct answer is \(4x\). The option \(8x\) may result from handling the negative signs while subtracting incorrectly. Exam tip: when a minus sign precedes brackets, change the sign of every term inside the brackets.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Exploring Algebraic Identities. Topic: Algebraic identities.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
