Linear Equation Word Problems - Examples & Practice

The population of the rhinoceros is decreasing due to poaching. Right now, in $2016$, there are about $5100$ rhinos in the wild. In the average year there is a net decrease of $100$ rhinos. If you model this with slope-intercept form $y=mx+b$, with $y$ being the population of rhinos and $x$ number of years after $2016$, what would $m$ and $b$ be?