# Cancelling effect of a system on a signal

I have a signal $$A(t)$$ and it's been transformed using an unknown system to a signal $$A'(t)$$. I also have another output signal $$B'(t)$$ from the same system and I want to retrieve the corresponding input signal $$B(t)$$. I wanted to first calculate the frequency response of the system, and then divide the Fourier transformed version of $$B'(t)$$ by it. Is this a good way? $$H(\omega) = \frac{A'(\omega)}{A(\omega)}$$ and then $$B(\omega) = \frac{B'(\omega)}{H(\omega)}$$ and then I can perform inverse Fourier transform on the $$B(\omega)$$. Is this a good and practical way? I'm trying to do it in Python or Matlab and I want it to be both theoretically and practically correct (I am a bit confused about doing the division part in my code.)