I think for this one, B seems the most right :)
Y=x^2-5
y=2x-5
y+5=2x
x=(y+5)/2
y=((y+5)/2)^2-5
y=(y^2+10y+25)/4-5
4y=y^2+10y+25-20
0=y^2+6y+5
0=(y+5)(y+1)
y= -5 or -1
y=2x-5 (y= -5 doesn't work for this one so use -1)
-1=2x-5
2x=4
x=2
Using these answers, you can choose answer D with reasonable certainty.
400 divided by 5 = 80.
Needs to bag at least 80.
Let [a, b] = the interval
The average rate of change can be found by using [f(b) - f(a)]/(b - a).
Let a = 1 and b = 5.
Let R = rate of change
17- x^2
R = [17 - 5^2] - [17 - 1^2]/(5 - 1)
R = [17 - 25] -[17 - 1]/4
R = [(-8) - (16)]/4
R = (-24)/4
R = -6
Done.
