Equation

A problem treated in the mathematical form of finding those inputs for which two given functions have equal outputs. The unknowns are the functional inputs, and the equal functional outputs are called solutions or roots. Solutions satisfy a given equation. The totality of solutions depends on the set of values that may be assigned to the unknows. Values of unknows that satisfy a set of equations characterize the set as a system of equations. Two systems (two equations) may stand in different relationships such as equivalence.