## Linear equation in two variables - ESSENTIAL POINTS

• Linear equation in two variables is an equation of the form ax + by + c = 0, where a, b and c are real numbers, such that a and b are not both not equal to zero.
• The solution of a linear equation is not affected when
• the same number is added to (subtracted from) both sides of the equation,
• both sides of the equation are multiplied or divided 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.
• The equation of the y-axis is x = 0 and the equation of the x-axis is y = 0.
• The graph of x = a is a straight line parallel to the y-axis and 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