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SAI International School
CLASS - IX

Mathematics
CHAPTER-4: Linear Equation in Two Variables

Lesson Notes-3

Sub Topic: Graph of Linear Equation

Graph of a Linear Equation in Two Variables: Linear means a lines. So, the graph of a
linear equation in two variables is a straight line.
 To draw the graph of linear equation in two variables, we need to find minimum

two solutions of the given equation, and then plot them on the Cartesian plane,
then join the points.
By joining these coordinates, we get the line of that equation.

 The coordinates which satisfy the given Equation lies on the line of the equation.

 Every point (x, y) on the line is the solution x = a, y = b of the given Equation.

 Any point, which does not lie on the line, is not a solution of Equation.

Example:
Draw the graph of the equation 3x + 4y = 12.

Solution:

To draw the graph of the equation 3x + 4y = 12, we need to find the solutions of the
equation.
Let x = 0

3(0) + 4y = 12

y = 3, (x, y) = (0, 3)

Let y = 0

3x + 4(0) = 12
x = 4, (4, 0)

Now draw a table to write the solutions.

X 0 4

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