# Are the graph y=9 and  x=5 perpendicular?

May 18, 2016

They are perpendicular.

#### Explanation:

These are special cases of the equation of a line.

y = 9 is a ine parallel to the x-axis with a gradient = 0 and passing through all points in the plane with a y-coordinate of 9.

To graph select some points say, (-2 ,9),(0 ,9),(2 ,9),(5 ,9) and draw a straight line through them.

x = 5 is a line parallel to the y-axis , whose gradient is undefined and passes through all points in the plane with an x-coordinate of 5.

To graph select some points say, (5 ,-3),(5 ,0),(5 ,3),(5 ,5) and draw a straight line through them.

graph{(y - 0.001x - 9)(y - 1000x + 5000) = 0 [-25.99, 31.75, -6.83, 22.05]}