Plz help I don’t understand

You have to figure out the angle where the “?” is using vertical angles and parallel lines.

2) so you know a triangle is 180 degrees so for this one jsut subtract 180-84=96°
4) do the same (subtract)
9) you know you have a right angle so you have 21x+6=90 subtract 6 both sides and you have 21x=84 divide by 21 and now you have x=4

The last one bc that's a calendar