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Anonymous
Anonymous asked in Science & MathematicsMathematics · 7 days ago

Is -5 squared 25 or -25?

The problem only asks to find -5 squared, so I think it would be 25 because -5 times -5 is 25. However, my friend thinks -5 squared is -25. She thinks this because since it doesn't have parenthesis it would be mean the opposite of 5 squared. Therefore 5 times 5 is 25 and the opposite of that is -25. Who is right? 

27 Answers

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  • Anonymous
    3 days ago

    A negative times a negative number would always equal to a positive one but the answer could vary given the parenthesis. If somehow the value is (-5)² then the answer would still be 25, but if given, -(5)², one's task is to firstly solve and square it first before combining it with a negative value, which, in this case, the answer should be -25.

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  • DWRead
    Lv 7
    3 days ago

    It's not telling you to take -5 and square it. 

    It's telling you to take 5 and square it, then take the negative.

    -5² = -5·5 = -25

    (-5)² = (-5)(-5) = 25

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  • 5 days ago

    It depends, you should state whether a parenthesis is present or not. For example, -5^2 would be -25, while (-5)^2 would be 25. So, what the problem asks is not really specific, so I would have to say both you and your friend are correct

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  • Mark
    Lv 7
    6 days ago

    25.  5i squared would be -25.

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  • 6 days ago

    I can see why your friend is confused. parenthesis make the operation clear. When you ask me what -5 squared is, you can write it as (-5)^2, which, as you said, is 25. 

    If you were to write it as -(5)^2, then yeah it is -25.

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  • 6 days ago

    Given i^2 = -1 by definition, we have -5 = -1*5 = i^2 * 5; so that (i^2 * 5)^2 = i^4 * 5^2 = (-1)*(-1) * 5^2 = +1* 25 = 25  QED.

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  • 7 days ago

    Its better think about the concept of squaring: (-5)² = (-5). (- 5). But if you have any algebraic expression written -5 ^ 2 then the result will be: -5² = (-1) (5) (5) = - 25. Some small things can lead to confusion in mathematics.

    https://www.youtube.com/watch?v=AJUkb1X9wL8

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  • 7 days ago

    as others have said, english is ambiguous.

    (–5)² = 25

    –(5)² = –25

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  • fcas80
    Lv 7
    7 days ago

    The question is ambiguous.  Obviously parentheses would clear up the ambiguity.

    If you see the expression -x^2, most people agree that equals -1 times (x^2).  For example y = -x^2 is the upside down parabola y = -(x^2).  

    Therefore, I am going with -25.

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  • Jim
    Lv 7
    7 days ago

    (-5)(-5) = 25  << this is the assumed meaning

    - (5)(5) = -25  << If you wanted this, say the negative "of" 5 squared.

    Using English for math problems can be problematic unless specific.

    Even WA says it's 25

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