If (p(x)=5x+a) and (q(x)=7x-a), what is (q(x)-p(x))?
Answer and explanation
Correct answer: \(2x-2a\)
\(q(x)-p(x)=(7x-a)-(5x+a)\). Since a minus sign occurs before the second bracket, the signs of all its terms change: \(7x-a-5x-a=2x-2a\). Therefore, the correct answer is \(2x-2a\). \(2x\) would result only if the terms containing \(a\) cancelled, but here they give \(-a-a=-2a\). Exam tip: while subtracting polynomials, use brackets and change the sign of every term in the polynomial being subtracted.
Frequently asked questions
What is the correct answer to this question?
\(2x-2a\)
Why is this the correct answer?
\(q(x)-p(x)=(7x-a)-(5x+a)\). Since a minus sign occurs before the second bracket, the signs of all its terms change: \(7x-a-5x-a=2x-2a\). Therefore, the correct answer is \(2x-2a\). \(2x\) would result only if the terms containing \(a\) cancelled, but here they give \(-a-a=-2a\). Exam tip: while subtracting polynomials, use brackets and change the sign of every term in the polynomial being subtracted.
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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