An algebraic equation, such as y = 2x + 7 or 3x + 2y - z = 4, in which the highest degree term in the variable or variables is of the first degree. The graph of such an equation is a straight line if there are two variables
An equation of the form ax + b = 0 is a linear equation with x being the unknown variable For example, the equation 2x - 9 = 3 is a linear equation which can be re-written as 2x - 12 = 0