Answer
(a) Image below
(b) 0.24
(c) 0.24 centimeters per year.
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Work Step by Step
(a) When $x = 0$:
$$D(x) = 20 + 0.24(0) = 20$$
When $x = 1$ $$D(x) = 20 + 0.24(1) = 20.24$$
Plot the following points: $(0,20)$ and $(1, 20.24)$. Since this is a linear function, draw a line that passes through both points.
(b) Since this is a linear function : $D(x) = ax + b$:
Slope = a = 0.24
(c) Rate of change (sediment layer) in a linear function = slope = a = 0.24
In this case, since x is measured in years, and $D(t)$ in centimeters: $0.24 \space cm/year$