### 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?

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/