1Cademy - Addition Property of Equality

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Solving an Equation

Formula

Addition Property of Equality

The Addition Property of Equality states that if the same quantity is added to both sides of an equation, the two sides remain equal. Mathematically, for any numbers $a$ , $b$ , and $c$ :

If $a = b$ , then $a + c = b + c$

This property is a fundamental tool used to solve equations where a number is subtracted from the variable. To isolate the variable and "undo" the subtraction, the same number is added to both sides. For example, when solving an equation like $x - 5 = 8$ , adding $5$ to both sides isolates $x$ while maintaining the equality.