Answer :
Answer:
[tex]y=-3.2x+18.5[/tex]
Step-by-step explanation:
Let
x ----> the number of days
y ----> the amount of money remaining in dollars
we have the points
(2,12.10) and (5,2.50)
step 1
Find the slope m
The formula to calculate the slope between two points is equal to
[tex]m=\frac{y2-y1}{x2-x1}[/tex]
substitute the values
[tex]m=\frac{2.50-12.10}{5-2}[/tex]
[tex]m=\frac{2.50-12.10}{5-2}[/tex]
[tex]m=-3.2\ \$/day[/tex] ----> is negative because is a decreasing function
step 2
Find the equation of the line in slope intercept form
[tex]y=mx+b[/tex]
where
m is the slope
b is the y-intercept
with the slope m and the point (2,12.10) find the value of b
substitute
[tex]12.10=-3.2(2)+b[/tex]
solve for b
[tex]12.10=-6.4+b[/tex]
[tex]b=12.10+6.4[/tex]
[tex]b=18.5[/tex]
substitute
[tex]y=-3.2x+18.5[/tex]