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Maths Help (-x squared)

If you have -x^2 and you subsitute in 2, does this become +4 or -4?

Thanks

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Because a negative multiplied by another negative give you a positive the answer is +4.


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Original post by TomHibbs12
If you have -x^2 and you subsitute in 2, does this become +4 or -4?

Thanks


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Original post by Hollybollybee109
Because a negative multiplied by another negative give you a positive the answer is +4.


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The negative comes after the squaring, so it is -(2^2) = -(2*2)=-4
Okay it depends whether you mean (-x)^2 or -(x)^2. If you mean the first one, where the negative sign is in the brackets, you are doing -x times -x, and two negatives make a positive so the answer will be 4. If it's the second one, then you are doing -(x times x) so the answer is -(2 x 2)= -4.
The answer is +4.


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Original post by Hollybollybee109
The answer is +4.


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The answer is -4
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TomHibbs12
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Glad to see everyone's in agreement. Thanks for the answers - the question works if the answer is -4, but I was confused because I thought it would be +4. It has no brackets, simply -x^2
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TomHibbs12
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My thinking was it is essentially -1x^2, so x^2 multiplied by -1 would give you the answer
Like for example -3 x -10 = +30
-2^2 is the same as -2 x -2 = +4


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Original post by TomHibbs12
My thinking was it is essentially -1x^2, so x^2 multiplied by -1 would give you the answer


Yeah personally this is what I think so I think it should be -4
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B_9710
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Original post by Hollybollybee109
Like for example -3 x -10 = +30
-2^2 is the same as -2 x -2 = +4


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−x2 -x^2 is the same as −(x2) -(x^2) not (−x)2 (-x)^2 .
The back of the textbook can be wrong it has been many times before


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It is basic intergers


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ImageUploadedByStudent Room1473714244.786646.jpg


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razzor
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Original post by Hollybollybee109
The back of the textbook can be wrong it has been many times before


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I agree with Valerie. The answer is -4.
BIDMAS tells us that we work with indices before subtraction, so we must square the 2 first before dealing with the negative part.

-2² = -4

This is different to saying (-2)², in which case the answer would indeed be 4 as -2 x -2 = 4.
Original post by Hollybollybee109


We get that, we are trying to settle whether the question wants us to multiply two negatives or multiply two positives and then make it negative...
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Zacken
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Original post by Hollybollybee109
It is basic intergers


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Seems like you're having trouble understanding basic integers then.
Original post by ValerieKR
The answer is -4


I disagree.
By induction, it is clearly +-4


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Original post by Hollybollybee109
Like for example -3 x -10 = +30
-2^2 is the same as -2 x -2 = +4


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I agree


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