Hello

I need to prove this and im having som trouble doing it.

x(x(x-2)-(x-2)) = x(x-2)(x-1)

Thank you for any assistance.

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- Aug 19th 2008, 09:44 AMMladen1Prove
Hello

I need to prove this and im having som trouble doing it.

x(x(x-2)-(x-2)) = x(x-2)(x-1)

Thank you for any assistance. - Aug 19th 2008, 10:25 AMo_O
$\displaystyle x\left[x{\color{red}(x-2)}-{\color{red}(x-2)}\right]$

Focus on the inside expression. Factor the red out to get your desired answer.

If it helps, imagine $\displaystyle a = {\color{red}(x-2)}$.

We then have: $\displaystyle x[x{\color{red}a} - {\color{red}a}] = x[{\color{red}a}(x-1)]$ - Aug 19th 2008, 10:39 AMSoroban
Hello, Mladen1!

Quote:

I need to prove this and I'm having some trouble doing it.

. . $\displaystyle x[x(x-2)-(x-2)] \:= \:x(x-2)(x-1)$

**what**is stopping you?

[1] Multiply out both sides and show that they are equal! . . .*Duh!*

[2] Or we can factor the left side . . .

. . $\displaystyle x\bigg[x\underbrace{(x-2)} - \underbrace{(x-2)}\bigg]$

. . . . . common factor

. . . . . . .$\displaystyle \downarrow$ . .$\displaystyle \swarrow$

. .$\displaystyle = \quad\;\; x(x-2)(x-1) $