Complex sentence: Both stars exhibit random variation in luminosity due to flares and they have been given variable star designations: the brighter member Groombridge 34 A is designated "GX And", while the other component is designated "GQ And".
Split into simpler sentences: Both stars exhibit random variation in luminosity due to flares and they have been given variable star designations. The brighter member Groombridge 34 A is designated "GX And", and the other member is designated "GQ And".