The anwser is C because your suppose to line it up like this, 4x+4=6x-14, then you solve for x. Once you have x then you plug it in and solve. For your x you will get 9.
Opposite angles of parallelograms are congruent. Set the angle measures equal to each other and solve for x. 4x + 4 = 6x - 14; -2x = -18; x = 9. Plug 9 back into either angle measure: 4(9) + 4 = 40. m∠ACD = 40°.
