Answer:
[tex]y=-\frac{1}{20}x+5[/tex]
Step-by-step explanation:
Here we are given that the present height of the sand dune is 5 ft and it is eroding 1 ft in every 20 years. If x represent the number of years and y represents the height of the sand dune. Hence we can consider the coordinates be (0,5) (20,4) (40,3) (60,2) (80,1) (100,0)
Let us evaluate the equation of the line plotted on these coordinates
Here we can see the y intercept is 5
Let us find the slope
[tex]m=\frac{y_2-y_1}{x_2-x_1}\\m=\frac{5-4}{0-20}\\m=\frac{1}{-20}\\m=-\frac{1}{20}[/tex]
The equation in slope intercept form is given as
y=mx+c
where c is y intercept i.e. 5
[tex]y=-\frac{1}{20}x+5[/tex]
Hence this is our required equation
