What is the equation of the line passing through #(9,2)# and #(9,14)#?

2 Answers
May 8, 2016

#x=9#

Explanation:

As it is a line that passes through #(9,2)# and #(9.14)#, when either abscissa or ordinate is common, we can easily find the equation of the line - as it will of the form #x=a#, if abscissa is common and of the form #y=b#, if ordinates are common.

In the given case, abscissa is common and is #9#, hence equation is #x=9#.

May 8, 2016

#x=9#

Explanation:

Gradient #->("change in y")/("change in x")#

Let point 1 be:#" "P_1->(x_1,y_1)->(9,2)#
Let point 2 be#" "P_2->(x_2,y_2)->(9,14)#

Notice that there is no change in #x#

This means that the line is parallel to the y axis (vertical)
Put another way: #x# is always 9 and you may allocate any value you wish to #y#

The way to write this mathematically is #x=9#