Theory:

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.
The equation in which two variables involved, each of which is in the first degree. These variables are arranged so that they are not multiplied by each other is called a linear equation in two variables.
Example:
\(x+y = 2\), \(x+2y = 6\), \(3x = 9y\), \(-2y+\frac{1}{4} = 4x\)
These equations are called as linear equations in two variables.