Respuesta :

If UT is a midsegment,
  SR = 2·UT
  7x-1 = 2(3x+1)
We can add 1-6x to solve this
  x = 3

Then the length SQ is twice the length of SU.
  SQ = 2(2x+2) = 2(2·3+2)
  SQ = 16