Give the geometric representations of 2*x* + 9 = 0 as an
equation

(1) in one variable

(2) in two variables

(1) In one variable, 2*x* + 9 = 0 represents a point
as
shown in the following figure.

(2) In two variables, 2*x* + 9 = 0 represents a straight line
passing through point

(−4.5, 0) and parallel to *y*-axis.
It is a collection of all points of the plane, having their
*x*-coordinate as 4.5.

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