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**Neha****Member**- Registered: 2006-10-11
- Posts: 173

Sqrt( 6x - 2) - sqrt(9) = 5

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**Devantè****Real Member**- Registered: 2006-07-14
- Posts: 6,400

Well, first try simplifying it.

√(6x-2) - √9 = 5

√(6x-2) - 3 = 5

√(6x-2) = 8

We know that √64 = 8

So √(66-2) = 8

x = 11

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**Toast****Real Member**- Registered: 2006-10-08
- Posts: 1,321

Hmmm, that last bit's a bit confusing, I would write it out fully:

√(6x-2) = 8

6x-2 = 64 [square both sides

6x = 66

∴x = 11

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**Devantè****Real Member**- Registered: 2006-07-14
- Posts: 6,400

I somehow doubt squaring both sides here would be useful to be honest, it's just down to recognising squares.

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**Neha****Member**- Registered: 2006-10-11
- Posts: 173

that wht i had also......

but its wrong

why

if u put in 11...

6 * 11 =66

66 - 2 = 64

sqrt64 = 8

then ohhhhhhhhhhhhhhhhhhhhh myyyyyy god

lol u know hwt i did

i did teh same thing that you all did but at teh end i said sqr8 - sqrt9 lol

ohhhhh my god

thanks guys

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**Devantè****Real Member**- Registered: 2006-07-14
- Posts: 6,400

No problem, Neha.

Feel free to ask away.

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**Toast****Real Member**- Registered: 2006-10-08
- Posts: 1,321

Devanté wrote:

I somehow doubt squaring both sides here would be useful to be honest, it's just down to recognising squares.

I've never learnt that method before, it sounds strange

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

It's practically the same as squaring both sides, really. He's just not saying so, and skipping a few steps. That's fine for relatively simple problems like this, but if you tried that with a more complicated problem then you might confuse yourself.

Your way is pretty much the same as his, but clearer and with more intermediate steps.

Why did the vector cross the road?

It wanted to be normal.

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