Simple algebra question $$\dfrac{\qquad\dfrac{5p+10}{p^2-4}\qquad}{\dfrac{3p-6}{(p-2)^2}}$$ 
Im all confused about this question. Can someone go through it step by step. Can you please list when I can cancel numbers. Thanks. 

Remember that
$$\frac{\quad\frac{a}{b}\quad}{\frac{c}{d}} = \frac{a}{b}\div \frac{c}{d} = \frac{ad}{bc}.$$
If you think of the fraction as a "sandwich", with $a$ and $d$ the bread, $b$ and $c$ the ham-and-cheese, then the bread goes on top and the ham and cheese go on the bottom.
Alternatively, dividing by $x$ is the same as multiplying by $\frac{1}{x}$, and 
$$\frac{1}{\quad\frac{c}{d}\quad} = \frac{d}{c}$$
so
$$\frac{\quad\frac{a}{b}\quad}{\frac{c}{d}} = \frac{a}{b}\times\frac{1}{\quad\frac{c}{d}\quad} = \frac{a}{b}\times \frac{d}{c} = \frac{ad}{bc}.$$
