In mathematics, the equality between two algebraic expressions is called an equation, which will be called members of the equation. In equations, they will appear related through mathematical operations, numbers and letters (unknowns).
Most mathematical problems find their conditions expressed in the form of one or more equations.
Meanwhile, when any of the values of the variables in the equation meet equality, this situation will be called the solution of the equation.
Before an equation the following scenarios can occur, that none of the values of the unknown reach equality, or on the contrary, that every possible value of the unknown fulfills it, in this case we would be faced with what is called identities in mathematics and when two mathematical expressions coincide in the inequality, it will be determined as inequality.
There are various types of equations, among them, we find the functional equation, which is one in which the constants and variables involved are not real numbers but functions. When a differential operator appears in some of the members, they are called differential equations. Then there is the polynomial equation, which will be the one that establishes the equality between two polynomials. On the other hand, first degree equations are those in which the variable x is not raised to any power, with 1 being its exponent. Meanwhile, the characteristic and differential feature of equations known as second degree equations is that they will have two possible solutions to it.
But for astronomy, where the term also says present, an equation is the difference between the place or average movement and the true or apparent that a star has.