What Is the Difference Between the Graphs Of $\mathrm{y}<\mathrm{mx}+\mathrm{b}$ And $\mathrm{y} \leq \mathrm{mx}+\mathrm{b}$

What is the difference between the graphs of $\mathrm{y}<\mathrm{mx}+\mathrm{b}$ and $\mathrm{y} \leq \mathrm{mx}+\mathrm{b}$ ?