From the given function, to explain the correct answer I will plot the graph for :
y(t)=-t^2+14t-40
thus the graph will be as shown in the figure:
From the graph we deduce that the correct statement is:
y'(t)=-2t+14=0
thus
t=7
thus
y(7)=0
thus the correct statement is:
<span>c. The average rate of change over the interval 6≤t≤8 is 0</span>
y(t)=-t^2+14t-40
thus the graph will be as shown in the figure:
From the graph we deduce that the correct statement is:
y'(t)=-2t+14=0
thus
t=7
thus
y(7)=0
thus the correct statement is:
<span>c. The average rate of change over the interval 6≤t≤8 is 0</span>