Equations are a fundamental concept in mathematics, used in many fields such as algebra, geometry, analysis, and probability. They are used to solve problems by finding the values of unknowns that satisfy a certain condition. Equations are often represented in the form of an equality between two expressions, with an equal sign in the middle. For example, the following equation:
contains the unknown x and asks to find what value of x makes the equality true.
For example, the equation 2x + 3 = 7 has a unique solution, which is x = 2. By substituting this value into the equation, we obtain:
The equality holds, so the value x = 2 is indeed a solution of the equation.
Some equations may also have complex solutions, which are imaginary numbers. For instance, the quadratic equation x² + 1 = 0 has no real solution, but it does have a complex solution x = i, where i is the imaginary unit.
Among the common resolution methods, we find:
The substitution method: by replacing one expression with another at each step, the equation is simplified until only one unknown remains.
The elimination method: by adding or subtracting equations to eliminate one unknown at each step, the equation is reduced to a form where only one unknown remains.
The Cartesian product method: by using value tables to test different combinations until finding those that satisfy the equation.
The graphical method: by graphically representing the equation on a Cartesian plane, one finds the intersection points between the curve and the x-axis that represent the solutions of the equation.
The resolution method depends on the type of equation and the mathematical tools available to us. It is important to choose the appropriate method to obtain the correct solutions.