Which form can be used to find ( 48^2 ) easily?
Answer and explanation
Correct answer: \((50-2)^2\)
Since \(48=50-2\), it is convenient to write \(48^2\) as \((50-2)^2\). Using \((a-b)^2=a^2-2ab+b^2\), we get \((50-2)^2=50^2-2\times50\times2+2^2\). In contrast, \((48+2)(48-2)\) equals \(48^2-2^2\), not \(48^2\) directly. Exam tip: for quick squaring, express a number near 10, 50, or 100.
Frequently asked questions
What is the correct answer to this question?
\((50-2)^2\)
Why is this the correct answer?
Since \(48=50-2\), it is convenient to write \(48^2\) as \((50-2)^2\). Using \((a-b)^2=a^2-2ab+b^2\), we get \((50-2)^2=50^2-2\times50\times2+2^2\). In contrast, \((48+2)(48-2)\) equals \(48^2-2^2\), not \(48^2\) directly. Exam tip: for quick squaring, express a number near 10, 50, or 100.
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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