Iodine (¹³¹I), which is initially at rest, decays into xenon (¹³¹Xe) through the emission of a beta particle, which in this case is an electron. The decay is as follows:

¹³¹I → ¹³¹Xe + e⁻

Formulate an equation for the conservation of relativistic energy in this decay in terms of masses of iodine (mᵢ), xenon (mₓ), and the electron (mₑ), along with their relativistic factors: xenon (γₓ) and the electron (γₑ).