We live in a world that is completely dominated by the CBSE pattern of education especially us, Indians. There are a lot of books available in the market which the teachers as well as students use for self-understanding of any subject but the best in them have proved to be the RS Aggarwal books. These books have been written by a person named RS Aggarwal himself who has a doctorate (PHd), so these books can be completely reliable. The RS Aggarwal books are completely CBSE based books and are the most used when it comes to the recent times. These are the NCERT books. Some advantages that NCERT possesses are:

- It forms guidelines meaning one receives the knowledge about what kind of topics, chapters and questions are included in a particular course.
- It does not miss out on covering all topics because CBSE follows NCERT.
- It consists of some really fun activities and interesting examples meaning it always associates a question with a real life concept/example.
- Always focuses on explains concepts from basics because it provides a recap of the study matter from the previous year.
- These books are sufficient for scoring at-least 90%.

Talking about the RS Aggarwal books from the students’ perspective, these books have answers and topics given in points. Comparing these books to their counterparts, these books are more student-friendly as they have answers given in points and everybody knows that studying in points helps students to remember better. It tries to cover almost every topic out there related to the subject.

From the point of view of the school examinations, RS Aggarwal books help in scoring more and better marks. The level of these books, their methods of teaching and their mode of practice can help students score excellent marks in their CBSE boards. These books are a suitable choice for anyone wanting to attempt the government competitive exams as these books are filled with a variety of questions, useful and important concepts for a higher level of study. These books are also used for Olympiad and scholarship examinations. But majorly the RS Aggarwal books are recommended for school examinations. Many teachers also use these books for their self-study assessment and also use them to educate children on various topics. The RS Aggarwal books are very prominent among the class 8 students especially due to their knowledge-

rich content that guides the students perfectly in all the subjects. Students heavily refer to the mathematics book because it offers complete set of questions, previous year question papers, interesting activities for the students to self-perform and much more.

Now, the most important chapter of this books is considered to be the 8th one that is the linear equations chapter. Anywhere you search or type on the internet, this chapter is the first one to pop up. A lot of videos have been made on this chapter.

So in order to represent this chapter, a go-through should be done.

## What are linear equations?

A Linear equation is an algebraic equation/expression involving variables where, the highest power of the variable is one.

A Linear question has:

- At least one variable.
- Highest power of the variable is 1.
- An equality sign is a must.

There are two kinds of this which are the linear equations in one variable and linear equations in two variables equations which are the first degree equations.

### 1. 4 added to a number gives us 10, find out that number.

Now anyone can easily calculate and find the answer to be ‘6’ but that’s not how we have to calculate here. In other way we’ll just assign a variable to the missing number and write down the equation as:

x + 4 = 10.

This type is calculation comes in handy while trying to find out values much greater than this in a simpler form. These can be performed in two ways the inverse operations way or the transpose way but most of the times the Transpose method is the more preferred one.

For example:

4x + y = 6,

Where, x and y are the variables, 6 is the constant and 4 is the coefficient.

The power of the ‘x’ variable is 1 and the power of ‘y’ variable is also 1 so the biggest power here remains 1 and hence this equation is known as a One degree equation or linear equation.

Another example,

2xy + 5 = 10,

Here, the The power of the ‘x’ variable is 1 and the power of ‘y’ variable is also 1 so 1+1 = 2 and therefore its not a linear equation.

The reason an equation is called as linear or first degree equation is because here the highest power of the variable is 1.

### 2. 2x + 5y = 12

X-y =4,

Each equation here has two variables but how do we describe them.

It can be easily described as

ax + by = c, or

ax + by + c= 0,

Writing the linear equations in two variables in both of these ways is correct.

a, b and c are the constants and x and y are the variables.

But there are some conditions attached to these and they are that a, b and c should be real numbers and both a and b cannot be zero together, at least one has to be non-zero.

This lesson is completely and well explained if class 8 students refer to the RS Aggarwal books. As many questions can be asked based on this topic in examination, one needs to be well prepared and understand this concept well in order to attempt them neatly in exams without getting stuck.

In the general world as well, there is a lot of importance given to the linear equations.

They help in making predictions, calculating rates and making conversions.

They can also be used to figure out income over time, to calculate mileage rates and to predict profit or loss. The real strength lies on the equations which describe various features of the world in an extensively precise way.

There can be infinitely a lot of solutions to the linear equations if someone takes an extreme interest in maths and decides to solve it all.

Also Reffer: RS Aggarwal Class 8 Solutions Chapter 8 Ex 8A