X=20

Given AB||CD||EF, ∠ABC = 70° and ∠CEF = 130°

AB||CD

Therefore,

∠ABC = ∠BCD = 70° [Alternate angles] ________________ (i)

EF||CD

Therefore,

∠DCE + ∠CEF = 180°

⇒ ∠DCE + 130° = 180°

⇒ ∠DCE = 50°

Now,

∠BCE + ∠DCE = ∠BCD

⇒ x + 50° = 70°

⇒ x = 20°