# algebra manipulation problem

• April 10th 2008, 01:06 PM
Ant
algebra manipulation problem
hi,

$5x(3x+2)-3(3x+2)=(3x+2)(5x-3)$

I know this is pretty basic stuff but could someone please talk me through this? I can see that one bracket is made up of the common factor and the other is made of the two number which were outside the bracket, but how does this work?

Thanks
• April 10th 2008, 01:08 PM
o_O
To make it easier to see, set $u = 3x + 2$

So we have:
$5x(3x+2) - 3(3x+2) = 5x(u) - 3u = u(5x - 3)$

See how the u factors out? It probably just looked more complicated but if you boil it down, it isn't so bad ;)
• April 10th 2008, 01:12 PM
Ant
ah, thanks, it really is much clearer when you call u = 3x+2.

Thanks again.