Final answer:
The black hole in a high-mass X-ray binary is significantly more massive than the one in a low-mass X-ray binary, with the former often being upwards of 10 solar masses and the latter closer to 3 solar masses.
Step-by-step explanation:
The mass of the black hole in a high-mass X-ray binary is generally much larger than the mass of the black hole in a low-mass X-ray binary. In the context of stellar-mass black holes, which are black holes with masses ranging from a few to several tens of solar masses, we observe that high-mass X-ray binaries tend to have black holes that can have masses upwards of 10 times the mass of the Sun, such as Cygnus X-1 which has an invisible companion with about 15 solar masses.
Low-mass X-ray binaries, on the other hand, typically have black holes that are closer to the lower limit of stellar black hole mass, around 3 solar masses. Therefore, comparing the two, the black hole in a high-mass X-ray binary can be several times more massive than the one in a low-mass X-ray binary, though the exact mass can vary depending on the specific system.