Final answer:
Without specific context, we have various possible equations related to television sets such as the linear regression pricing model or the physics of x-ray generation, but cannot determine an exact equation for an 'X-large television set'.
Step-by-step explanation:
The question seems to be asking about an equation related to television sets but the information provided covers a range of topics including the equation for change in length in materials (possibly thermal expansion), linear relationships and pricing of television sizes, the inductive reactance represented as XL in relation to frequency, the effect of magnetism on cathode ray tube (CRT) television screens, and the generation of x-rays in color television tubes.
Given the scattered information, it is challenging to provide a specific equation for an 'X-large television set' as the student's question suggests without more context.
However, based on the details presented, various equations that could be relevant include the linear regression equation d. ŷ=-745.252 + 54.75569x, which might relate to pricing models, for each additional inch, the price increases by $54.76, or the physics-related calculation of the shortest wavelength of x-rays generated by a television tube, depending on what aspect of the television set they are referring to.