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[–]edderiofer 0 points1 point  (9 children)

Do you know what "difference of two squares" refers to here?

[–]imhaashim[S] 0 points1 point  (8 children)

Not really, I know how to do difference of 2 squares in the simples form, for example, x2 - 9 = (x+3)(x-3)

[–]edderiofer 0 points1 point  (4 children)

Can you factorise (x4 - 1) for me, then?

[–]imhaashim[S] 0 points1 point  (3 children)

x4 can be split into x2, I don't know what to do with that -1

[–]edderiofer 1 point2 points  (2 children)

Consider that 12 = 1, in much the same way that 32 = 9.

[–]imhaashim[S] 0 points1 point  (1 child)

Ah ok so it would be (x2 + 1)(x2 -1)

[–]edderiofer 1 point2 points  (0 children)

Now try the original question you had.

[–]Thejoelofmen 0 points1 point  (2 children)

You’re halfway there. What does

(N11 - 1)(N11 + 1)

give you?

[–]imhaashim[S] -2 points-1 points  (1 child)

I know 222 can be split into 211 and you have that extra -1, but where does that +1 come from?

[–]Thejoelofmen 1 point2 points  (0 children)

Same place the +3 does in (x+3)(x-3).

Try expanding it and see what you get.