NCERT Solutions Class 9th Maths Chapter – 4 Linear Equations in Two Variables Exercise – 4.4

Question 1 Give the geometric representations of y = 3 as an equation
(i) in one variable

Solution: y = 3
∵ y = 3 is an equation in one variable, i.e., y only.
∴ y = 3 is a unique solution on the number line as shown below:

(ii) in two variables

Solution: y = 3
We can write y = 3 in two variables as 0.x + y = 3
Now, when x = 1, y = 3 (1, 3)
x = 2, y = 3 (2, 3)
x = -1, y = 3 (-1, 3)

Question 2 Give the geometric representations of 2x + 9 = 0 as an equation
(i) in one variable

Solution: In one variable,
2x + 9 = 0
2x = -9
x = -9/2
x = -4.5
(ii) in two variables

Solution: In two variables,
2x+9 = 0
2x+0y+9 = 0
When y = 0, x = -4.5
When y = 1, x = -4.5