Respuesta :

if SQ bisects ∡RST, that means SQ is cutting it into two equal halves, namely ∡TSQ = ∡RSQ, and since we know that ∡RSQ = 2x - 4, then ∡TSQ = 2x - 4, thus

∡RST = ∡TSQ + ∡RSQ

∡RST = (2x - 4) + (2x - 4)

∡RST = 4x - 8.