An equation is a type of exercise that carries a $=$ sign which, on each side of the sign, that is, in each member of the equation there is an algebraic expression.

An algebraic expression can be anything -> just a number, just an unknown or well, an exercise with number and unknown.

- In an equation the unknown can appear several times
- In an equation several unknowns can appear

**First-degree equation**** ->** It is an equation whose unknown is raised to the first power.

**Quadratic equation**** –>** It is an equation whose unknown is squared, that is, raised to the second power.

Perform several mathematical operations on both sides of the equation at the same time to isolate the variable (leave it alone on one side of the equals sign) and solve for it.

The equation will be solved once you manage to arrive at a true statement.