We do not really consider the constants in time complexity. It does not matter if there is some constant being multiplied with time complexity or being added/subtraced/divided.
O(n+k)/O(kn)/O(n-k)/O(n/k), they all are same. Because they do not effect the time complexity much. However, if the time-complexity is effected exponentially. For example, in
O(log n)
then that does matter. I hope it helps