Awhat are two angles that share a common vertex and a common side

Solve: 3x+y=6 4x-2y=18 show all work !

Joanie watched 1 out of three of a movie in the morning

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap