The addition property of equality justifies this. You could also say that she simply subtracted 7, and then it would be the subtraction property of equality. This is the case because if you add or subtract (or multiply or divide) the same number on both sides of an equation, the equation will still be the same.
Hope it helps!
1/2 I guess I don't think you typed in the question correctly. Not trying to be mean.
Answer:
Its 6 cookies per day
Step-by-step explanation:
12/2=6 6 cookies per day
There is 3 variable, in this case, painters, walls and time(minutes). You need to find how many painters needed and provided information on the walls and time(minutes).
Increasing walls will cause more painter needed. It was reversed in time which was increased time will cause less painter needed.
In this case, you need to divide the variable walls with time since it reversed so: 27wall/9 minutes
It equal to : 3 walls/minute
Information provided is:
3 painters= 3 walls/3 minutes
Equal to : 3 paintes= 1 wall/minute
To make it 3 walls/minute, the painter needed will be:
(3 walls/minute) / (1 wall/minute) x 3 painters= 9 painters
Answer: 9 painters