The floating point representation of a real number $x$ in a machine is given by $fl(x)=x(1+delta),: |delta| = frac{|x^*-x|}{|x|} le epsilon$.

But I do not find this equation very insightful. Insert $delta = frac{x^*-x}{x}$ in the equation and you get $x^*$. So $fl(x)$ is just $x^*$. Why write $x^*$ in this fancy way: $$fl(x)=x(1+delta)$$

Does equation have a name by the way?