The length of PQ is 20 units
From the given triangle PQ = 2ST
Given the following parameters
PQ = -4x + 32
ST = 37 - 9x
Equate both expression:
-4x + 32 = 2(37 - 9x)
-4x + 32 = 74 - 18x
14x = 74 - 32
14x= 42
x = 3
Get the length of PQ
PQ = -4x + 32
PQ = -4(3) + 32
PQ = 20
Hence the length of PQ is 20 units
Learn more on median property of a triangle here: https://brainly.com/question/16189203