Answer
a. $\frac{4}{5}$
b. $8/5$
c. $3$
d. $0$
Work Step by Step
Plug in each variable into the function and evaluate, as each point is in the form of (x, y, z):
a. $\frac{3-(-1)}{(-1)^2+(2)^2}=\frac{4}{5}$
b. $\frac{1-1/2}{(1/2)^2+(-1/4)^2}=\frac{1/2}{5/16}=8/5$
c. $\frac{0-(-1/3)}{(-1/3)^2+(0)^2}=\frac{1/3}{1/9}=3$
d. $\frac{2-2}{(2)^2+(100)^2}=0$