Given: AB || CD and BC || DE.
∠ABC = 75°.
Since AB || CD, BC will be the transversal.
∠ABC = ∠BCD = 75° ( Alternate interior angles) -----(i)
As BC || DE, CD will be the transversal.
∠BCD + ∠CDE = 180° (Co-interior angles)
From (i), 75° + ∠CDE = 180°.
⇒ ∠CDE = 180° - 75° = 105°.
⇒ x = 105°.