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Ok guys so I've been out of school for eight years, never used algebra again, also I was forcibly removed from school in 9th grade. I need to ask a few questions on Elementary Algebra, what are the () in an equation? For Example:

2x+4y(-4)/8x(-3)x

Not sure what in the world to do :X sorry guys, it's been so long. If anyone could give me a quick crash refresher course that would be greatly appreciated! I took a practice test and scored 25% when back in school I could just whizz by all of this stuff!

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    $\begingroup$ Mathoverflow is filled with serious mathematicians who don't want to waste their time on easy problems. $\endgroup$ Aug 15, 2013 at 20:53
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    $\begingroup$ I don't think calling the guys in mathoverflow "whiners" is nice. For one, many of the people here are also members there. Second, I very much doubt anyone would be willing to give you a course in anything: it is not what this site is for. If you have some doubts and you do some effort and need some guidance fine, but if you really need a course then some personal tutoring is, probably, best suited. $\endgroup$
    – DonAntonio
    Aug 15, 2013 at 20:54
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    $\begingroup$ The braces are there because $8x(-3)x$ actually stands for $8\cdot x\cdot (-3) \cdot x$. The braces avoid having $\cdot -$ since this is ugly. :) $\endgroup$ Aug 15, 2013 at 20:54
  • $\begingroup$ Ok so the braces only stand for multiply? I will call them whiners as I didn't even know this site existed as it is so far down the list. Mathoverflow was the first thing I saw, instead they could have pointed me here. I was asking for an actual course but a quick refresher. Meaning just like Dima McGreen, simplifying the equation to better understand it and explaining what it does. Thank you Dima! I know math, I've known mathematical equations though like I've stated it's been years since I've need it. Even in my algorithms for coding! $\endgroup$
    – EasyBB
    Aug 15, 2013 at 21:00
  • $\begingroup$ And if this was easy, which I am sure it is, though I didn't know what to call them to search for it on Google, you could have simply posted an answer and I would have checked it and be done with it. $\endgroup$
    – EasyBB
    Aug 15, 2013 at 21:01

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Actually, just putting two symbols next to one another stands for "multiply". So, for example $xy$ really means $x \times y$.

Parentheses are usually for gathering things together and keeping them separate from the other symbols in the formula. This removes ambiguity that arises from order of operations, so $x(y+z)$ means $x$ times $y+z$. This is obviously different from $xy +z$. Since you've done some programming, you are probably familiar with this idea.

In the specific case of things that are preceded by minus signs, the parentheses are for clarity, and to make things look nicer. So $x(-y)$ means $x$ times $-y$. If you leave out the parentheses, you have to write $x \cdot -y$ or $x \times -y$, or $x * -y$, which all look a bit odd. If you leave out the multiplication symbol, and you don't use parentheses, then you get $x - \!\!y$, which means something different.

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  • $\begingroup$ Thanks bubba that actually helped me quite a bit to understand all of it! That was an awesome quick refresher. $\endgroup$
    – EasyBB
    Aug 16, 2013 at 19:04

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