Answer:
This is the same as writing m = (d-n)/7
The parenthesis are essential for the second format because it tells us to divide all of (d-n) over 7, and not just n over 7.
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Step-by-step explanation:
Here is one way to solve for m. I'll go over each step in the next section below.
The idea is to get the variable m by itself.
Think of n+7m as 7m+n since we can add in any order. Then undo the "plus n" portion by subtracting n from both sides (step 3).
In the 4th step, I divided both sides by 7 to undo the multiplication that is going on with 7m aka 7*m
In general we follow PEMDAS backwards to undo each operation done to the variable we're solving for. Let me know if you have any questions about what I mean.