NCERT Class 9 Maths Linear Equations In Two Variables

4.1 Introduction
In earlier classes, you have studied linear equations in one variable. Can you write down a linear equation in one variable? You may say that x + 1 = 0, x + 2 = 0 and 2 y + 3 = 0 are examples of linear equations in one variable. You also know that such equations have a unique (i.e., one and only one) solution. You may also remember how to represent the solution on a number line. In this chapter, the knowledge of linear equations in one variable shall be recalled and extended to that of two variables. You will be considering questions like: Does a linear equation in two variables have a solution? If yes, is it unique? What does the solution look like on the Cartesian plane? You shall also use the concepts you studied in Chapter 3 to answer these questions.
4.2 Linear Equations
Let us first recall what you have studied so far. Consider the following equation: 2x + 5 = 0
ts solution, i.e., the root of the equation, is 5/2 − . This can be represented on the number line as shown below:

Please refer to attached file for NCERT Class 9 Maths Linear Equations In Two Variables