The cost of a pen is twice a notebook. Write a linear equation in two variables to represent this situation.

Given, that the cost of a pen is twice a notebook.

Now, let the cost of a pen be x.

And, let the cost of the notebook be y.

Then, according to the question,

Cost of a pen = twice the cost of a notebook

i.e. x = 2y

x−2y = 0

Hence, the required linear equation in two variables is x−2y = 0