What is the value of (-7^2)?
Answer and explanation
Correct answer: -49
The governing concept is the order of operations, especially the precedence of exponents over a unary minus. In the expression -7^2, there are no parentheses around -7, so the exponent applies to 7 first: 7^2 = 49. The negative sign then remains in front, giving -(49) = -49. Therefore, option B is correct. Option A, 49, would be obtained from (-7)^2, where the negative number is explicitly included in parentheses. Options C and D incorrectly treat the exponent as if it meant multiplication by 2 rather than squaring. Thus, careful attention to parentheses and exponent precedence resolves the question.
Frequently asked questions
What is the correct answer to this question?
-49
Why is this the correct answer?
The governing concept is the order of operations, especially the precedence of exponents over a unary minus. In the expression -7^2, there are no parentheses around -7, so the exponent applies to 7 first: 7^2 = 49. The negative sign then remains in front, giving -(49) = -49. Therefore, option B is correct. Option A, 49, would be obtained from (-7)^2, where the negative number is explicitly included in parentheses. Options C and D incorrectly treat the exponent as if it meant multiplication by 2 rather than squaring. Thus, careful attention to parentheses and exponent precedence resolves the question.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Polynomials. Topic: Operations on real numbers and the laws of exponents.
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