An equation is an expression along with an equal sign (=)
Equations are classified into two main groups'' linear equations and nonlinear equations. Examples of linear equations are as
x + 13 = 15
7x + 6 = 0
Nonlinear equations in the variable x are equations whether x appears in the second or higher degrees. They involve cubic and quadratic equations amongst others. For an example:
5x2 + 3x + 7 = 0 is quadratic equation
2x3 + 4x2 + 3x + 8 = 0 is cubic equation
The equations'' solution or the values of the variables for that the equations hold is named as the roots of the equation or the solution set.