Let DD be an interior point of the acute triangle ABCABC with AB>ACAB > AC so that DAB=CAD\angle DAB = \angle CAD. The point EE on the segment ACAC satisfies ADE=BCD\angle ADE = \angle BCD, the point FF on the segment ABAB satisfies FDA=DBC\angle FDA = \angle DBC, and the point XX on the line ACAC satisfies CX=BXCX = BX. Let O1O_1 and O2O_2 be the circumcentres of the triangles ADCADC and EXDEXD, respectively. Prove that the lines BCBC, EFEF, and O1O2O_1O_2 are concurrent.