Question 1135658
what is the average rate of change of {{{f(x)= -2/x^2}}} from {{{x=1}}} to {{{x=2}}}? 

All you need to find is :

{{{(f(2)-f(1))/(2-1)}}}

{{{f(1)= -2/1^2=-2}}}
{{{f(2)= -2/2^2=-2/4=-1/2}}}

then:

{{{(f(2)-f(1))/(2-1)=(-1/2-(-2))/(2-1)=(-1/2+2)/1=3/2}}}