Answer:
-18
Step-by-step explanation:
f(x) = x² - 3x -10
f(-10) = (-10)² – 3(-10) – 10
f(-10) = 100 + 30 - 10
f(-10) = 120
f(-5) = (-5)² – 3(-5) – 10
f(-5) = 25 + 15 - 10
f(-5) = 30
=====
The <em>average rate of change</em> is the slope m of the straight line joining the two points.
m = (y₂ - y₁)/(x₂ - x₁)
m = (30 - 120)/(-5 – (-10))
m = -90/(-5+10)
m = -90/5
m = -18
