5r=20 10p=100 14t=42
100+42+20=162
5r+10p+14t=$162
        
             
        
        
        
Step-by-step explanation:
the slope is the ratio of "y coordinate difference / x coordinate difference".
so, let's find 2 good points (I mean by that with integer coordinates). I see e.g.
(-1, -1) and (0, -7)
x changes by +1 (from -1 to 0).
y changes by -6 (from -1 to -7).
so, the slope is -6/1 = -6.
D is the right answer. 
 
        
             
        
        
        
Slope  =  (change in 'y') / (change in 'x')
If you find two points where the line goes through the corners of boxes,
then count up the 'y' boxes and the 'x' boxes between those two points,
you'll find that the line rises 3 y-boxes for each x-box.
The slope of the line is  3 . 
        
             
        
        
        
Equation showing relationships between things you are conparing. An equals sign represents the two expeessions are equal