Marlene S. answered 09/18/20
5x-4
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P Q R
x+6 3x
The segment addition postulate states tells us that PQ + QR = PR
So,
x+6 + 3x = 5x-4
combine like terms
4x+6 = 5x-4
And solve the algebraic equation
Subtract 4x from both sides
6 = x-4
Add 4 to both sides
10 = x
PQ = x+6 = 10+6 = 16