Answer:
y = 0.7(x^2 - 64x - 576)
Average rate of change = -49.
Step-by-step explanation:
As the x intercepts are -8 and 72 we can write the equation
y = a(x + 8)(x - 72) where a is some constant to be found.
As it passes through point (62, -490) we have, substituting:
-490 = a(62+8)(62-72)
-490 = - 700a
a = 0.7
So the equation of the parabola
y = 0.7(x + 8)(x - 72) or
y = 0.7(x^2 - 64x - 576).
Average rate of change between x = -8 and x = 2
= [0.7(2+ 8)(2 - 72) - 0.7(-8+8)(-8-72)] / (2 - -8)
= -490 - 0 /10
= -49
