could you help me please?

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Find x :
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Sum of adjacent angles on a straight line is 180.

∠ABY + ∠YBC = 180
x + 25 + 2x + 50 = 180
3x + 75 = 180
3x = 105
x = 35

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Check if AC is parallel to DF :
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If AC is parallel to DF, 
∠YBC = ∠BEF (Corresponding angles)

∠YBC = 2x + 50 = 2(35) + 50 = 120
∠BEF = 5x - 55 = 5(35) - 55 = 120

Since ∠YBC = ∠BEF, AC and DF are parallel.

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Answer: Since ∠YBC = ∠BEF, AC and DF are parallel.
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