Solve

Solve[equationvars]
attempts to solve equation for the variables vars.
Solve[equationvarsdomain]
restricts variables to domain, which can be Complexes or Reals.

Apply the solution:

Contradiction:

Tautology:

Rational equations:

Transcendental equations:

Solve can only solve equations with respect to symbols or functions:

This happens when solving with respect to an assigned symbol:

Solve a system of equations:

An underdetermined system:

Domain specification: