Answer:
Option C is correct
Addition property of Equality justifies the step.
Explanation:
Given the system of equation: x+y = 8 and x-y = 2.
Addition Property of Equality: The method of solving systems of linear equations is the addition Property, in which the two equations are added together to eliminate one of the variables.
Adding the equations states that we add the left sides of the two equations together, and we add the right sides together.
Using the addition property in equation: x+y=8 and x-y =2
then,
or
=10
Eliminate the y- variable; we have
2x=10
Therefore, the only property justifies the step is, Addition Property of Equality.