In the diagram, \angle ABD∠ A B D and \angle BDC∠ B D C are supplementary, the measure of \angle EDF=9x^\circ∠ E D F = 9 x ∘, and the measure of \angle ABD\:=\:\left(2x+105\right)^\circ.∠ A B D = ( 2 x + 105 ) ∘ .
Based on this information, which equation can be used to find the value of x?