solve help please tryed many ways..all came out wrong

Neha · 2006-12-22 04:57:13

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

Devantè · 2006-12-22 05:05:45

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

Toast · 2006-12-22 05:10:34

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

Devantè · 2006-12-22 05:12:02

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

Neha · 2006-12-22 05:18:15

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

Devantè · 2006-12-22 05:20:03

No problem, Neha.

Feel free to ask away.

Toast · 2006-12-22 07:07:29

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

mathsyperson · 2006-12-22 07:16:10

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.

Math Is Fun Forum

#1 2006-12-22 04:57:13

solve help please tryed many ways..all came out wrong

#2 2006-12-22 05:05:45

Re: solve help please tryed many ways..all came out wrong

#3 2006-12-22 05:10:34

Re: solve help please tryed many ways..all came out wrong

#4 2006-12-22 05:12:02

Re: solve help please tryed many ways..all came out wrong

#5 2006-12-22 05:18:15

Re: solve help please tryed many ways..all came out wrong

#6 2006-12-22 05:20:03

Re: solve help please tryed many ways..all came out wrong

#7 2006-12-22 07:07:29

Re: solve help please tryed many ways..all came out wrong

#8 2006-12-22 07:16:10

Re: solve help please tryed many ways..all came out wrong

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