Equation (+ what is the unknown) - Examples, Exercises and Solutions

But before explaining what unknowns are, it is important that we review the concept of what a mathematical equation is:

• An equation is an algebraic expression that includes numbers (fixed values), and also letters with unknown value (unknowns). Our goal is to arrive at a solution to the equation, that is, to find the missing value (the unknown), so that both sides of the equation are equal.

In general, we express the unknowns with the letters $X$, $Y$ or Greek letters such as alpha and beta. Most of the time we will be asked to find the unknown value to be determined by solving an equation.