Slope using two points is given by formula
[tex] m=\frac{y_2-y_1}{x_2-x_1} [/tex]
plug the given points
[tex] m=\frac{-6-2}{-16-(-4)} [/tex]
[tex] m=\frac{-8}{-16+4} [/tex]
[tex] m=\frac{-8}{-12} [/tex]
[tex] m=\frac{2}{3} [/tex]
Hence required slope is 2/3.