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| Question 1206470:  find the slope of a line that is perpendicular to the y-axis and passes through the point(-7,8)
 Found 2 solutions by  Theo, ikleyn:
 Answer by Theo(13342)
      (Show Source): 
You can put this solution on YOUR website! a line parallel to the x-axis has the form y = k. a line parallel to the y-axis has the form x = k.
 
 a line is formed by two points.
 the points are (x1,y1) and (x2,y2)
 
 the slope of the line is equal to (y2 - y1) / (x2 - x1)
 
 if the line is parallel to the x-axis, then y2 = y1 and the slope becomes 0 / (x1 - x1) = 0.
 
 if the line is parallel to the y-axis, then x2 = x1 and the slope becomes (y2 - y1) / 0 which is undefined.
 
 if the slope is 0, the line is parallel to the x-axis.
 if the slope is undefined, the line is parallel to the y-axis.
 
 if the line is parallel to the x-axis, it is perpendicular to the y-axis.
 if the line is parallel to the y-axis, it is perpendicular to the x-axis.
 
 your line is perpendicular to the y-axis which means it is parallel to the x-axis.
 
 that means that y2 = y1 which means that the slope is 0.
 
 the equation of your line is therefore y = 0x + b which becomes y = b, where b is the y-intersect.
 
 the line passing through the point (-7,8) and perpendicular to the y-axis is the line y = 8.
 
 x can be any value and the y-value will always be 8.
 
 here's the graph.
 
 
   
 you can see that, no matter what the value of x is, y will always be 8.
 
 you can see that the line is parallel to the x-axis which makes it perpendicular to the y-axis.
 
 the x-axis is a horizontal line at y = 0.
 the y-axis is a vertical line as x = 0.
 
 
 
Answer by ikleyn(52876)
      (Show Source): 
You can put this solution on YOUR website! . find the slope of a line that is perpendicular to the y-axis and passes through the point(-7,8)
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 To answer this question, you should not make any calculations, and the given coordinates
 of the point are excessive unnecessary information.
 
 Any straight line in a coordinate plane, perpendicular to y-axis, is parallel to x-axis and has zero slope.
 
 
 That is all.
 
 
 
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