Wednesday, 27 February 2013

Algebra... Which is larger? (II)


Jennifer says, "5x2  is always smaller than  (-5x)2. "

Do you agree? Explain your answer. 

Enter your response in Comments.

This question is compulsory.

18 comments:

  1. no, i do not agree.

    because in " (-5x)^2 " the magnitude and the negative sign are both in the bracket, there fore you would have to square the whole thing, inclusive of the negative sign. a negative x a negative gives you a positive and therefore when you square a negative number, it becomes a positive, so you can just ignore the negative sign in " (-5x)^2 " and calculate 5x^2 to get your ans. since " (-5x)^2 " is the same as 5x^2,the statement "5x2 is always smaller than (-5x)2 " is wrong.

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  2. No.
    Since both x has the same value and when two negative number multiplied together will be a positive number,the two sums above will be the same as (5x)(5x) is equal to (-5x)(-5x).

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  3. No. Both equations when done would give the same answer.

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  4. No.If you work out both the equations,the answer will be the same so Jane is wrong.

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  5. No. The answer will be the same as the second equation has a bracket so the negative sign will be included in the multiplication and hence the answer will be the same.

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  6. no the answer will become the same when both equation are evaluated

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  7. No. When X is an any no. no matter what the answer become the same. (5X)*(5X) = (-5X)*(-5X) Since negative and negative gives us positive

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  8. No, indeed not. The answer will be the same.

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  9. I do not agree because the number does not change at all except for the negative sign which will be turned into a positive sign when it is squared. Hence it does not change.

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  10. No I do not agree. Because since -ve * -ve = +ve, (-5x)^2 can be simplified to 5x^2. Therefore the answers would be the same for both equations

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  11. I do not agree. Both values have the same answer. Positive*positive=positive and Negative*negative=positive, hence there is no difference.

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  12. I do not agree as once you worked them out, the answers would be the same and there's no difference in the answers at all.

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  13. I do not agree as 5x^2 is equal to (5x)(5x) . (-5)^2 is (-5)(-5) will be same as (5)(5) because the two negative signs are changed to positive.

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  14. Let's expand it:
    5x^2 = 5 * x^2
    (-5x)^2= (-5)(-5)(x)(x)
    =25x^2
    SO when we compare (-5x)^2 and 5x^2,
    (-5x)^2 is greater.
    So i don't agree with her.

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  15. This comment has been removed by the author.

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  16. The answers will be the same as (-)x(-)=(+) so i dont agree with Jennifer

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  17. The answers are the same
    5x^2 = 5 * x * x.
    (-5x)^2 = 5*x*x(The negative signs will be cancelled.)

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  18. Looks like almost all disagree that 5x^2 is always smaller than (-5x)^2.
    Some claim that they are the same - ok, when you choose one 'special' value to test.
    Does anyone else have a different view?

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