The steps are duplicated.Then, first I will write the steps in the right form:
19 = 5x - 1
20 = 5x
4 = x
Now, I will write the steps with the justification
19 = 5x - 1.... start
20 = 5x ..... Reason: addtion property of equality (you get this by adding +1 to both sides of the previous equality)
4 = x .... Reason: division property of equality (you get this by dividing by 5 both sides of the previous equality)