Analysis: as shown in the figure, if the angle BAD=x degrees and the angle DAC=y degrees, then the angle ABD=x degrees?

Because? Angle ADC= angle BAD+ angle ABD, angle ADC= angle ACD.

So: Angle ADC= Angle ACD=2x.

Because? Angle BAC=63, so: angle BAD+ angle DAC = X+Y = 63...( 1)

Angle ADC+ Angle ACD+ Angle DAC = 2x+2x+Y = 180...(2)

The solution of (1)(2) is: x=39, y=24.

So what? Angle DAC=24 degrees