# RS Aggarwal Chapter 4 Class 9 Maths Exercises 4.2 (ex 4b) Solutions

RS Aggarwal Chapter 4 Class 9 Maths Exercise 4.2 Solutions: In this chapter, the knowledge of linear equations in one variable shall be recalled and extended to that of two variables.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. Know more at the parent blog.

EXERCISE – 4B

## Important Definition for RS Aggarwal Chapter 4 Class 9 Maths Ex 4b Solutions

### Linear equation in one variable

When an equation has only one variable of degree one, then that equation is known as linear equation in one variable.

### Linear equation in 2 variables

When an equation has two variables both of degree one, then that equation is known as linear equation in two variables.

### The solution of linear equation in 2 variables

A linear equation in two variables has a pair of numbers that can satisfy the equation. This pair of numbers is called as the solution of the linear equation in two variables.

### Graphical representation of a linear equation in 2 variables

• Any linear equation in the standard form ax+by+c=0 has a pair of solutions in the form (x,y), that can be represented in the coordinate plane.
• When an equation is represented graphically, it is a straight line that may or may not cut the coordinate axes.

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