Respuesta :
Answer: [tex]\displaystyle m = \frac{d-n}{7}[/tex]
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.
============================================================
Explanation:
Here is one way to solve for m. I'll go over each step in the next section below.
[tex]d = n+7m\\\\n+7m = d\\\\7m = d-n\\\\m = \frac{d-n}{7}[/tex]
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.
