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factorise x^2-49

the answer is (x-7) (x+7) but is it correct if you write (x-7)^2
(edited 7 years ago)

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Reply 1
Avatar for _Xenon_
_Xenon_
12
Edit: You're wrong mate
(edited 7 years ago)
Reply 2
Avatar for D.SHA64
D.SHA64
OP
14
Original post by _Xenon_
Yes that is the same thing


edit:i know
thanks anyway
(edited 7 years ago)
Original post by D.SHA64
the answer is (x-7) (x-7) but is it correct if you write (x-7)^2

No (x+7)(x-7)
(edited 7 years ago)
Reply 4
Avatar for Zacken
Zacken
22
Original post by D.SHA64
the answer is (x-7) (x-7) but is it correct if you write (x-7)^2


Original post by _Xenon_
Yes that is the same thing


No, the answer is (x-7)(x+7).
Reply 5
Avatar for fatiana
fatiana
22
first of all its (x-7) (x+7)
and when you expand it you get x2-49
Original post by D.SHA64
the answer is (x-7) (x-7) but is it correct if you write (x-7)^2


If it were (x-7)(x-7) then it is the same as (x-7)^2 - however, it is not (x-7)^2 in this case. (x-7)^2 gives x^2 - 14x + 49 when expanded.
Reply 7
Avatar for Zacken
Zacken
22
Original post by undercxver
That's not the answer. To find your answer use this formula:
However yes (x-7)(x-7)=(x-7)2


Or use difference of two squares.
Original post by D.SHA64
the answer is (x-7) (x-7) but is it correct if you write (x-7)^2


Shouldn't the answer be (x + 7) (x -7). Your answer is wrong so you can't use any of those you wrote.
Original post by Zacken
No, the answer is (x-7)(x+7).


I was actually waiting for your response to this :tongue:
Reply 10
Avatar for ozzie2
ozzie2
12
Original post by D.SHA64
the answer is (x-7) (x-7) but is it correct if you write (x-7)^2


That's not correct, as that would expand to be x^2 - 14x + 49. The correct answer is (x-7) (x+7)
Original post by D.SHA64
thanks:smile:
it didnt say anything the mark scheme so i was just wondering


It edit
Reply 12
Avatar for D.SHA64
D.SHA64
OP
14
Original post by ozzie2
That's not correct, as that would expand to be x^2 - 14x + 49. The correct answer is (x-7) (x+7)


yeah your right and everyone else who said it
i misread the mark scheme
(edited 7 years ago)
(x-7)^2 would be (x-7)(x-7) so that would be wrong
Oh dear. You'd expect the first respondent to correct the OP and close the matter immediately :unimpressed:
Original post by Zacken
No, the answer is (x-7)(x+7).


Oh yeah sorry, didn't really look at that...
I assumed he was right because he said so and just looked at brackets to say (x-7)(x-7) would mean (x-7)^2

👍

Which is why you don't assume things are correct!!!)
Original post by niv1234
(x-7)^2 would be (x-7)(x-7) so that would be wrong


That's correct.

Posted from TSR Mobile
Reply 17
Avatar for Zacken
Zacken
22
Original post by rosemondtan
I was actually waiting for your response to this :tongue:


How come? :tongue:
Reply 18
Avatar for Zacken
Zacken
22
Original post by ServantOfMorgoth
That's correct.

Posted from TSR Mobile


No, it's not. (x−7)(x−7)=(x−7)2≠x2−49(x-7)(x-7) = (x-7)^2 \neq x^2 - 49. Look up difference of two squares or factorising polynomials if you're still confused.
Original post by Zacken
How come? :tongue:


I saw the thread and the first few comments and I just had this feeling that you would be here to correct it in no time :giggle: turns out I was right!! :redface:

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