Thread: Factorising

does anybody know how this came from?

thank you

They use the fact that 5! = 5* 4! and 4!= 4*3! to change 8!/(4!*4!) into 8!/(4!*(4*3!)) and 8!/(5!*3!) into 8!/((5*4!)*3!) to get 4!3! in the denominator of both quantities then factorise 8!/(4!3!)

for multiplicatin instead of (×), ( . ) is used
8!/4!.4! + 8!/5!.3!
= 8!/4!.4! + 8!/4!.5.3!
= 8!/4![1/4! + 1/5.3!]
= 8!/4![1/3!.4 + 1/5.3!]
= 8!/4!.3![1/4 + 1/5]
----

Originally Posted by pspss

for multiplicatin instead of (×), ( . ) is used
8!/4!.4! + 8!/5!.3!
= 8!/4!.4! + 8!/4!.5.3!
= 8!/4![1/4! + 1/5.3!]
= 8!/4![1/3!.4 + 1/5.3!]
= 8!/4!.3![1/4 + 1/5]
----

Actually, a (.) is used as a decimal point, it's actually a centred dot, which is used for multiplication. Though a is also acceptable as long as it doesn't get mixed up with any variables.

Originally Posted by cxz7410123

does anybody know how this came from?

thank you

The solution has already been given, but I thought I'd rewrite it a bit:


We have a forum that deals with how to write expressions. It's the LaTeX Help forum. It's pretty easy to learn the basics.

-Dan