View Full Version : Algebraic nightmare
iAMfromHuntersBar
Jun 6, 2007, 03:28 PM
Hi guys!
Right, I've got this maths question, and it's the first time in ages I've been honestly stumped as to where to even start! It's like this;
x(squared) − x = 0
now I know that to get rid of the x squared I need to square root it, and thus both sides... but is that where I start?
Cheers everyone!
J
Curlyben
Jun 6, 2007, 03:31 PM
x^2-x=0
is what you mean.
rather than rooting this is a quadratic so solve in the form
(x+a)(x+b)=x^2 +abx +ab=0
so we're looking at ab = -1
but that isn't going to work, bugger.
Monkey boy or Galactus or Alpha will be along in a bit
Ps try the [ MATH ] tag to get it to display properly with x^2= x^2
galactus
Jun 6, 2007, 04:33 PM
Just lookng at this we can see the answer is 0 or 1.
x^{2}-x=0\Rightarrow{x(x-1)}=0
iAMfromHuntersBar
Jun 7, 2007, 12:06 PM
sorry, I still don't understand!
I can see that x^2 - x = 0
is the same as (x * x) - x = 0
and that 0 and 1 are the only possible answers, but is that right, and is that a good enough explanation?
rockerchick_682
Jun 7, 2007, 12:16 PM
you factor it out x2-1=0 to x(x-1)=0
and if you're trying to find the roots, then the roots are x=0 and x=1
iAMfromHuntersBar
Jun 7, 2007, 12:24 PM
Lol, sorry, I'm being thick here, how do you get from;
x^2 - 1 = 0 to x(x - 1) = 0 though, what do you mean factor it?
sorry again!
rockerchick_682
Jun 7, 2007, 12:42 PM
I'm not sure how to explain it, but if you distributed x(x-1) you'd get x2-x because x*x=x2 and x*-1=-x, does that help?
snoopycool24
Jun 8, 2007, 06:20 PM
You can use the quadratic formula, too.
hemant_pandey
Aug 15, 2007, 11:53 PM
Hi guys!
Right, I've got this maths question, and it's the first time in ages I've been honestly stumped as to where to even start! it's like this;
x(squared) − x = 0
now I know that to get rid of the x squared I need to square root it, and thus both sides ... but is that where I start?
Cheers everyone!
J
Dear member this is a basic query of algebra.x^2-x=0 can be solved by taking x common.Hence x(x-1)=0 or x-1 and x=1
Capuchin
Aug 16, 2007, 12:13 AM
I can't believe I missed this when it came about. Hope it's not too late hunter. You just factor by x.
iAMfromHuntersBar
Aug 16, 2007, 12:20 AM
It's too late for the paper I was submitting... but I'd still like to understand it better, which I don't! Lol!
But it's far too early and I haven't had nearly enough coffee to think about anything, let alone algebra! Ha ha!
Capuchin
Aug 16, 2007, 12:21 AM
\frac{x^2-x}{x} = x-1
therefore:
x^2-x = x(x-1)
Does that make sense?
iAMfromHuntersBar
Aug 16, 2007, 12:32 AM
I think so, because you have removed the "divided by x" on one side you therefore multiply the right-hand side by x?
Capuchin
Aug 16, 2007, 12:33 AM
Yes, I was just trying to demonstrate that the two are equal.
Does the initial division make sense to you?