Which of the following trinomials is equivalent to the expansion of \((2x+3y)^2\) and is therefore a perfect-square trinomial?
Answer and explanation
Correct answer: \(4x^2+12xy+9y^2\)
Using \((a+b)^2=a^2+2ab+b^2\), take \(a=2x\) and \(b=3y\). The middle term is \(2(2x)(3y)=12xy\), so A is correct. B has 6xy instead. Exam tip: verify a perfect square by checking twice the product of the square roots of the end terms.
Frequently asked questions
What is the correct answer to this question?
\(4x^2+12xy+9y^2\)
Why is this the correct answer?
Using \((a+b)^2=a^2+2ab+b^2\), take \(a=2x\) and \(b=3y\). The middle term is \(2(2x)(3y)=12xy\), so A is correct. B has 6xy instead. Exam tip: verify a perfect square by checking twice the product of the square roots of the end terms.
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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