# Math Help - rearranging fractions

1. ## rearranging fractions

Hi,

Im doing a Maths course and I am finding the basics very difficult. the last time I did Maths was at O Level over 20 years ago and my poor ancient mind seems to have forgotten most of it. Anyway at the moment I am more interested in the how things happen then actual answers and I was hoping someone could explain the following

Why and how does p+q/pq become 1/q+1/p

How is it possible to simplify (x-√3)(x+√3) to x² - 3

Thanks

2. ## Re: rearranging fractions

It's important to know some important algebraic rules.
$\frac{p+q}{pq}=\frac{p}{pq}+\frac{q}{pq}=\frac{1}{ q}+\frac{1}{p}$
Second question, use the fact that $(a-b)\cdot (a+b)=a^2-b^2$