<span>Answer 61 73-66= 7 21-13 = 8 ?? -52= 9 20-10 = 10 ??=61</span>
Answer:
Here we have the function:
S(t) = 500 - 400*t^(-1)
Then the rate of change at the value t, will be:
S'(t) = dS(t)/dt
This differentiation will be:
S'(t) = -400/t^2
Then:
a) the rate of change at t = 1 is:
S'(1) = -400/1^2 = -400
The rate of change after one year is -400
b) t = 10
S'(10) = -400/10^2 = -400/100 = -4
The rate of change after 10 years is -4, it reduced as the years passed, as expected.
If there are 20 groups of 10, then there are 200 pencils. Subtract 200 and 137 to get the number of dull pencils.
Hi,
Work:
Equation;

Roots: (-9, 0), (8, 0)
Domain: x = R
Minimum: (-1/2, -289/4)
Vertical intercept: (0, -72)
Hope this helps.
r3t40