In order to get the value of n, which is what we are trying to find, it is important to know how to isolate the variable.
When something is added to n, you subtract to isolate n. Going with this logic, you would multiply by a number if you wanted to isolate n with a fraction.
The first step would be to get rid of the 4 on the left side so we can work on the variable. We can do this by subtracting both sides by 4, so the left side cancels out to 0.
Next, we can multiply both sides by 5, so we can isolate the variable, because it is being divided by 5.
n=-40