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Chapter 8 Linear Equations in Two Variables Ex 8.4

Question 1.
Give the geometric representations of y = 3 as an equation
(i) in one variable.
(ii) in two variables.
Solution:
The given linear equation is
y=3 …(i)
(i) The representation of the solution on the number line is shown in the figure below, where y = 3 is treated as an equation in one variable.
NCERT Solutions for Class 9 Maths Chapter 8 Linear Equations in Two Variables Ex 8.4 img 1
(ii) We know that, y = 3 can be written as
0 . x + y = 3
which is a linear equation in the variables x and y. This is represented by a line. Now, all the values of x are permissible because 0 . x is always 0.
However, y must satisfy the equation y = 3.
Note that, the graph AB is a line parallel to the x-axis and at a distance of 3 units to the upper side of it.

Question 2.
Give the geometric representations of 2x + 9 = 0 as an equation
(i) in one variable.
(ii) in two variables.
Solution:


NCERT Solutions for Class 9 Maths Chapter 8 Linear Equations in Two Variables Ex 8.4 img 4

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