Final answer:
Adding equations is a legitimate method in solving systems because it utilizes the elimination process to simplify the system. It also respects the fundamental properties of equations and provides a precise analytical technique for finding solutions, which can be more accurate than graphical methods.
Step-by-step explanation:
Adding equations, known as the method of elimination, is a valid method for solving a system of equations. This approach works because it leverages the property that if two equations both equal the same variable, they can be added together to eliminate one of the unknowns, simplifying the system. For instance, suppose we have equation a: x + 2y = 6, and equation b: 3x - y = 4. Adding them gets 4x + y = 10, which is a new equation that can help solve for one of the variables more directly. This takes advantage of the fact that equations describe relationships between variables that hold true under various mathematical operations, including addition.
Another key aspect is the understanding that solutions to equations are often not unique when they include an unknown squared, leading to two potential solutions. However, contextual knowledge can determine which solution is reasonable, such as in physics problems where time or velocity must make sense in the real world.
Moreover, while analytical methods of solving systems are precise, solving equations graphically can offer a visual understanding but may lack accuracy due to potential scaling and drawing inaccuracies. Therefore, analytical techniques, like adding equations, are generally more accurate but can be complemented with graphical methods for a better conceptual grasp.