The system has no solutions.
To do this question I started out by trying to solve the simultaneous equations using substitution.
First we can simplify 6x = 12y - 24 by dividing everything by 6, which gives us:
x = 2y - 4
Then we can substitute this into the second equation:
30y - 15(2y - 4) + 30 = 0
30y - 30y + 60 + 30 = 0
90 = 0
As this is obviously not true, we can conclude that the system has no solution.
I hope this helps! Let me know if you have any questions :)