Proportion

Al-Allo · 2013-02-02 05:16:57

I just have a little problem :

X 8
_= _
7 9

If I would want to solve for X, I would multiply by 7 for each side. Leaving x=56
___
9
But what I did is x=56
__
63
Could somebody explain me why it's wrong ?
Thanks

bobbym · 2013-02-02 06:26:06

When you multiply by 7 you cancel the 7 on the left but not the 9 on bottom right.

Correct thing to do is to cross multiply

9x = 56

x = 56 / 9

Al-Allo · 2013-02-02 06:30:18

But I mean not canceling the 9 but multiplying it by 7, it's not a right thing to do ? Thanks

bobbym · 2013-02-02 06:34:45

If you multiply by 7 you are going to get:

x = 56 / 9 which is the same thing.

Al-Allo · 2013-02-02 07:28:41

bobbym wrote:

If you multiply by 7 you are going to get:
x = 56 / 9 which is the same thing.

ok, I understood. Thanks

Last edited by Al-Allo (2013-02-02 07:30:14)

bobbym · 2013-02-02 07:32:09

Hi;

You are welcome.

Math Is Fun Forum

#1 2013-02-02 05:16:57

Proportion

#2 2013-02-02 06:26:06

Re: Proportion

#3 2013-02-02 06:30:18

Re: Proportion

#4 2013-02-02 06:34:45

Re: Proportion

#5 2013-02-02 07:28:41

Re: Proportion

#6 2013-02-02 07:32:09

Re: Proportion

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