Question

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

(1) in one variable

(2) in two variables

Answer 1

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

(2) In two variables, 2x + 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.