1. Introduction to linear equation in two variable

What is a linear equation in two variable?

 

A linear equation in which two variables are involved in which each variable is in the first degree.

 

It can be written in the form of $ax+by+c = 0$ where $a$, $b$ and $c$ are real numbers, both $a$ and $b$ are not equal to zero, $x$ and $y$ are variables and $c$ is a constant.

These equations are called as linear equations in two variables.