the steps derek used to solve an equation are shown below.
Solve: 0.4x + 5 + 0.2x = 17
Step 1 : 0.4x + 0.2x + 5 = 17
Step 2: 0.6x + 5 = 17
Step 3: 0.6x = 12
Step 4: x = 20
Which properties justify step 1 and step 3?