Any straight line on the coordinate plane can be described by the equation
y=mx+b
Where:
x,y are the coordinates of any point on the line
m is the slope of the line
b is the intercept (where the line crosses the y-axis) .
The slope m can be found beetween two points on the line:
[tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex]
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]
In this case, the points is on the y-axis (0,300) and the x-axis (450,0), whereby the slope m is found:
[tex]m=\frac{y_2-y_1}{x_2-x_1} = \frac{0-300}{450-0} = -\frac{2}{3}[/tex]
We already have b, because b is the point, where the line crosses the y-axis.
b=300
So the equation is:
[tex]m=-\frac{2}{3} \\b=300\\y=mx+b[/tex] ⇒ [tex]y=-\frac{2}{3} +300[/tex]
The graph is attached.
