Addition property of equality is used
Solution:
Given that,
We have to find the property of equality or congruence that justifies going from the first statement to the second statement
Given is:
3a - 6 = 54
3a = 60
It is clear that, addition property of equality is used
The property that states that if you add the same number to both sides of an equation, the sides remain equal
The equation remains to be true, if we add or subtract same number on both sides of equation
Therefore,
3a - 6 = 54
Add 6 on both sides of equation
3a - 6 + 6 = 54 + 6
3a = 54 + 6
3a = 60
Thus addition property of equality is used