Since the dilatation is centred at the origin then multiply each of the coordinates of the vertices by the scale factor.
(- 4, 2 ) → (- 4, 2 ) → (- 2, 1 )
Similarly
(- 2, 8 ) → (- 1, 4 )
(2, 4 ) → (1, 2 )
The final price would be $35.10, hope this helps. :)
Not sure about 5 and 8 however
6: Function. Every Y input has only 1 X input
7: Not a function
9: Not a function
10: Function