The graph shows a relationship between temperature and time.504030Temperature (°F)2010h246810Number of HoursWhich best represents the equation that shows the temperature, t, after h hours?tu-n +45t = -45ht = -5h + 45t= -3h + 45

as we can see in the graph we know that the equation that represents a line is the equation of the line
in this case
y=t
x=h
we need two points in order to calculate the slope
(0,45)=(x1,y1)
(5,30)=(x2,y2)
[tex]m=\frac{y2-y1}{x2-x1}=\frac{30-45}{5-0}=\frac{-15}{5}=-3[/tex]the y-intercept is 45
the form of the equation of the line is
[tex]y=mx+b[/tex]where
m=slope
b=y-intercept
in this case
m=-3
b=45
[tex]y=-3x+45[/tex]using the variables of the problem the equation that represents the problem is
[tex]t=-3h+45[/tex]the correct answer is the last one