Theory:

Let us consider an example to understand the concept of linear equations in two variables.
 
Jane loves apples and banana. So, she went to the shop and bought \(2\) apples and \(1\) banana for \($8\). Also, the cost of a banana is twice the cost of an apple. So, how can you determine the cost of \(1\) apple and \(1\) banana?
 
apple-1150560_1920.jpg
 
Let \(x\) denotes the cost of apple and \(y\) denote the cost of banana.
 
Now, let us write as linear equations in two variables we have already learnt in class \(9\).
 
Thus, we have:
 
\(2x + y = 8\) and \(y = 2x\)
 
The cost of \(1\) apple and \(1\) banana can be determined by solving these \(2\) equations. There are different methods of solving a pair of linear equations, which we will learn in this chapter.
Reference:
https://pixabay.com/photos/apple-banana-food-ripe-delicious-1150560/