In mathematics, a system of equations, also known as a set of simultaneous equations^{[citation needed]} or an equation system,^{[citation needed]} is a finite set^{[citation needed]} of equations for which common solutions are sought.^[1] An equation system is usually classified in the same manner as single equations,^{[citation needed]} namely as one of the following:

• System of linear equations
• System of nonlinear equations
• System of bilinear equations
• System of polynomial equations
• System of differential equations
• System of difference equations

• Simultaneous equations model, a statistical model in the form of simultaneous linear equations
• Elementary algebra, for elementary methods