Answer:
Identity property of addition
Explanation:
Given
Step 3: 6x = 12
Required:
Which property justifies Step 3 of his work
The property that justifies this step is the identity property of addition;
At step 2; the equation was
6x + 0 = 12
When 0 is added to any expression or number, the value of the number or expression remains unchanged.
So, when 0 is added to 6x on the left hand side of the equation, the value remains the same as follows:
So, 6x + 0 = 12 becomes
6x = 12.
This property is referred to as the Identity property of addition