"a" is not equal 0

The equation is a representation of the equality of two algebraic expressions. An equation is true (the equality of the expressions holds) if the value of its right-hand side and left-hand side are equal for a given value of the variable. The variable in the equation is called the unknown.

The values of the unknown for which the right-hand side and left-hand side of the equation are equal are called the roots of the equation or the solution of the equation.