What is the value of (13^2-12^2)?
Answer and explanation
Correct answer: 25
13^2=169 and 12^2=144, so 13^2-12^2=169-144=25. Alternatively, using the difference of squares identity a^2-b^2=(a-b)(a+b), we get (13-12)(13+12)=1×25=25. Therefore, option D is correct. Exam tip: For the difference between the squares of two close numbers, use the difference of squares identity for a quicker calculation.
Frequently asked questions
What is the correct answer to this question?
25
Why is this the correct answer?
13^2=169 and 12^2=144, so 13^2-12^2=169-144=25. Alternatively, using the difference of squares identity a^2-b^2=(a-b)(a+b), we get (13-12)(13+12)=1×25=25. Therefore, option D is correct. Exam tip: For the difference between the squares of two close numbers, use the difference of squares identity for a quicker calculation.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Number Systems. Topic: Exponents.
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