Changing the equation into slope form: 

, where 

 is the slope [gradient] and 

 is the y-intercept.




The gradient is 

 and y-intercept is at 

Graphing 

 using slope-intercept method:
a) The slope is a negative slope. The line will go 'down hill'
b) The line must pass the point (0, 490)
c) The line will intercept the x-axis at y = 0    
 
     
     
     
    
    So, x-intercept is at (735, 0)
The graph of this function is shown below. The intercepts are labelled at:
y = 490
x = 735
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Next month's profit equation

Rewriting this into slope-equation form



The gradient, 

, equals to 

The y-intercept, 

, equals to 531
The equation still has the same gradient with last month's profit equation but different y-intercept. 
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A linear graph show points of (0, 300) and (450, 0)
We work out the slope: 

Y-intercept at x = 0, so it's at y = 300
Equation 
