How do I add a linear slope equation (y-intercept form) to a graph in the latest version of numbers?

I recently spent a lot of time trying to figure out how to add a linear slope equation to the best fit line of a scatterplot graph in numbers, which was a requirement for a chemistry lab report I was working on. After failing to figure it out on my own or find any relevant info on the internet, I had to copy/paste my data into excel and do it from there. Does anybody know how I can do this in numbers? Obviously excel works just fine but I like the aesthetics and the simpler formatting options of the graphs that I get using numbers.