4 less than n is n minus 4
N-4 = -15
To solve, we move the constants to the other side, isolating n in the process which gives us its value.
The reason this works is because everything is still accounted for, so the answer or value of the equation doesn’t change.
To move the constant we have to add 4 to both sides to keep the value the same.
N - 4 + 4 = -15 + 4
N=-11