Check out the attached image. I drew what I think your book is showing. The figure on the left is triangle ABC without any extended segments. The figure on the right has segment AB extended shown in red. This forms the exterior angle x
The rule that connects x, y and z together is the remote interior angle theorem. It says that adding two interior angles is going to be equal to the exterior angle that is not touching either interior angle. The "remote" part means "far away" so just think of the two angles that are furthest way or not touching the exterior angle in question. 
In terms of algebra, the rule is
x+y = z
 
        
        
        
The equation for a line is y=mx+b. where m is the slope and b is the y intercept. 
The slope of 17 is provided. This means m=17. The point (0,0) tells you the y intercept is 0. This means b=0
Plugging these into the equation and simplifying:
y=17x+0
y=17x
Hope this helps :)
        
             
        
        
        
Answer:
you divied 7 by 14 which is 2
Step-by-step explanation:
 
        
             
        
        
        
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