**Linear Equations:**Any equation which can be put in the form ax + by + c = 0, where a, b and c are real numbers and a and b are not both zero is called a linear equation in two variables.

The solution of a linear equation is not affected when- the same number is added to (or subtracted from) both the sides of the equation.
- you multiply or divide both the sides of the equation by the same non-zero number.

- A linear equation in two variables has infinitely many solutions.

- The graph of every linear equation in two variables is a straight line.
- x = 0 is the equation of the y-axis and y = 0 is the equation of the x-axis.
- The graph of x = a is a straight line parallel to the y-axis.
- The graph of y = a is a straight line parallel to the x-axis.
- An equation of the type y = mx represents a line passing through the origin.
- Every point on the graph of a linear equation in two variables is a solution of the linear equation. Moreover, every solution of the linear equation is a point on the graph of the linear equation.
**Graph of a Linear Equation in Two Variables:**We know that a linear equation in two variables has infinitely many solutions. We write the solutions as a pair of values and plot, these points on a graph paper and join them to get a line.