Respuesta :

RT = RS + ST
8x - 43 = 2x - 4 + 4x - 1
8x - 43 = 6x - 5
8x - 6x = -5 + 43
2x = 38
x = 38/2
x = 19

QS = 2RS = 2(2x-4) = 2(2*19-4) = 2*34 = 68