The concept states that adding the same number to both sides of an equation preserves the equality. In simpler terms, if two expressions are equal, then adding the same value to each expression will not change the fact that they are equal. For example, if x = y, then x + z = y + z. This fundamental principle is applicable across all real numbers and extends to complex numbers as well.
This principle is essential for solving algebraic equations. It allows for the strategic manipulation of equations to isolate variables and determine unknown values. This technique simplifies complex equations into manageable forms, enabling efficient problem-solving in mathematics, physics, engineering, and various other scientific disciplines. Historically, the formalization of such properties of equality provided a robust framework for consistent and reliable algebraic manipulation.