Consider the function $f(x) = -5 x - 6$ and find the following:

a) The average rate of change between the points   $(-1, f(-1) )$   and   $( 1 , f( 1 ) )$ .

b) The average rate of change between the points   $(a, f(a) )$   and   $(b, f(b) )$ .

c) The average rate of change between the points   $(x, f(x) )$   and   $(x+h, f(x+h) )$ .