Find QR
QR + RS = QS
18 + x + 2x + 24 = 17

Answer:
QR = 10
Step-by-step explanation:
QR + RS = QS , substitute values
18 + x + 2x + 23 = 17 , that is
3x + 41 = 17 ( subtract 41 from both sides )
3x = - 24 ( divide both sides by 3 )
x = - 8
Thus
QR = 18 + x = 18 - 8 = 10