Substitution means replacing a variable in an equation with a proposed value, evaluating both sides according to the order of operations, and determining whether the resulting numerical statements are equal. This distinguishes a value that satisfies an equation from one that merely makes one side true and supports later reasoning about equivalent equations and algebraic solutions; the focus is on simple one-variable equations and does not include formal proof of identities, systems, or advanced symbolic verification.
To check whether a proposed value solves an equation, substitute it for the variable.
Example: Check whether is a solution to
Replace with :
Evaluate the left side:
Now compare both sides:
The two sides are equal, so is a solution to the equation.
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