Solving equation for x: 2(x + 4) = ax  TOPIC_SOLVED

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Solving equation for x: 2(x + 4) = ax

Postby Leonardo of Pisa on Sun Sep 12, 2010 7:41 am

I am stumped by a very simple equation that I am trying to solve for x.

2(x + 4) = ax. I know the answer is supposed to be x = 8/(a - 2), but I can't see how to get there.

I first cleared the parentheses: 2x + 8 = ax.

Then: 2x = ax - 8; which leads to x = ax/2 - 4.

But I can't seem to clear that right-hand x, or the a for that matter!

Beyond that I am lost; I know I am missing something simple, but what?

I've got a number of similar problems in my text and I need to understand the principal/process involved.

Many thanks in advance...
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Re: Solving equation for x: 2(x + 4) = ax  TOPIC_SOLVED

Postby little_dragon on Sun Sep 12, 2010 11:19 am

Leonardo of Pisa wrote:Then: 2x = ax - 8; which leads to x = ax/2 - 4.

you have x on both sides. do like they show here to get the x bty iteslf.
(go down to where it says "This next exercise requires a little "trick" to solve it:" & do like it shows)
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Re: Solving equation for x: 2(x + 4) = ax

Postby Leonardo of Pisa on Sun Sep 12, 2010 5:20 pm

G'day Little Dragon,

Very many thanks for pointing me to the "little trick". I had had a brief look at that page earlier, but hadn't read all the way down before deciding it was irrelevant. Careless! Must be more careful about that in the future.

I was glad to discover it was a "trick"; I had been trying to solve that problem for the past few days and was feeling a little stupid.

Best Regards,
Leonardo
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