In this maths **IIT JEE video lecture** is about the topic **straight lines**. Though this is a simple topic and has been in our syllabus for a long time. At JEE examination level you will understand the various other features of the topic straight lines.

Straight line is the simplest form of equation in **two-dimensional coordinate geometry**. The equation of a straight line is the simplest in the curve. Any axes are themselves in the form of straight lines. If you join any two points, then they make a straight line from one point to another. Now this line, on both the sides goes till infinity. In two-dimensional coordinate geometry, there is no end to the straight lines.

Line can be in any form. It can run parallel to the axes or it can be oblique or any other ways. Let we consider any type of line. Always remember that any kind of line running parallel or otherwise to the axes, are infinite.

Suppose we take an example of the equation of a **line** say 2x+y=4. Before this let us first understand what an equation is. Whether an equation is of straight line or a curve or anything, we need to understand as what does the word equation means in **coordinate geometry**. In this equation, x is the coordinate and y is the coordinate. Now if we substitute the value of x and y in the above equation, such that we get the value equal to 4. All the coordinates that satisfy the points on the curve as well are on that line as well.

While understanding the concept of equation of a **straight line**, understand the equation of a straight line with the supporting illustration as given in the video lecture.

Let us now talk about the equation of axes. We all know that there are two types of axes, x-axis and y-axis. Now if we consider the x-axis and ask what the value of y-axis is, then the answer will be 0. Similarly, if we consider the y-axis and ask what the value of x-axis is, and then the answer will be zero. For detailed understanding refer to the illustrations in the video.

Often in the process of learning some subject, we are unable to forget to understand the basic of a subject which may seem too simple to us. However, while watching these videos, remember to understand the concepts clearly. This will help you in understanding other concepts as well.