Which of the following algebraic identities is true for all real values of the variables?
Answer and explanation
Correct answer: \((a+b)^2=a^2+2ab+b^2\)
Multiplying \((a+b)(a+b)\) gives \(a^2+ab+ab+b^2=a^2+2ab+b^2\), so A is an identity. Option B misses the middle term \(2ab\). Exam tip: always check the middle term and its sign.
Frequently asked questions
What is the correct answer to this question?
\((a+b)^2=a^2+2ab+b^2\)
Why is this the correct answer?
Multiplying \((a+b)(a+b)\) gives \(a^2+ab+ab+b^2=a^2+2ab+b^2\), so A is an identity. Option B misses the middle term \(2ab\). Exam tip: always check the middle term and its sign.
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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