The slope of (19,-16), (-7, - 15)

(19-16), (-7, - 15)

(-15 - (-16) / (-7-19)

(1) / (-26)

1/-26 is the slope.

What you do is you basically subtract the x's and y's i forget exactly how my teacher explained it but this would be how you would do it you would always have the pairs on one side like how the - 16 and 19 is on one side, that's what you want.