We are given the following expression:
![d=5m+9n](https://img.qammunity.org/2023/formulas/mathematics/college/2yaw1pffi638572j7z9l9kz2t1d07bnw68.png)
First, we can swap the sides of the equality, so we have.
![5m+9n=d](https://img.qammunity.org/2023/formulas/mathematics/college/c46jouo4s480ju9wu6iyzugsafg1ac42ui.png)
Now, on the left side, every term without n goes to the other side, with different signal(+/-). So
![9n=d-5m](https://img.qammunity.org/2023/formulas/mathematics/college/ic8b2jzs5u5w72wlzb0d6quxn1q1tqtnij.png)
Now, since 9 is multiplying n, it goes to the other side dividing. The solution will be:
![n=(d-5m)/(9)](https://img.qammunity.org/2023/formulas/mathematics/college/90joeawsuldd8erq9w1jchbh1eiiceifu9.png)