Answer:
x = 8, y = 89/9
Step-by-step explanation:
Because of parallel lines, some angles are the same, see the attached image. That also means that (12x-28) + (9y-77) = 180 because they are half of an angle. So:
(12x-28) + (9y-77) = 180 ->
12x + 9y = 185.
Then,
(7x+12) = (12x-28) ->
x = 8.
We can plug that into the last equation:
12(8) + 9y = 185 ->
y = 89/9
:)
