The property for the missing justification is: A. addition property of equality.
What is the Addition Property of Equality?
If b - a = c, based on the addition property of equality, we can isolate b by adding a to both sides, i.e. b - a + a = c + a, to give us b = c + a.
Using the addition property of equality, 7 was added to both sides of the equation as shown in step 3.
Therefore, the missing justification is: A. addition property of equality.
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