Angle joined a paperback club for a $10 membership fee plus $5.99 per book which equation best represents this sentence

Which one ? is the answer and how to find this answer

1) in triangle the, what is the measure of angle t (in degrees)? 2) in triangle bat, the measure of angle b is 66∘, and the measure of angle t is 77∘.what is the measure of the exterior angle at a (in degrees)?

3x = 729 solve for x plz . it's urgent. will mark