http://prntscr.com/mvjxsf
Avg rate of change =
[ f(-2) - f(-5) ]
___________ =
-2 - (-5)
[ (-2)^2 - 4 ] - [ (-5)^2 - 4 ]
_____________________ =
3
[ 4 - 25 ]
__________ =
[ -21 ]
_____ =
-7
