Let's solve each equation separately:

9(3x-7) + 3(8x-11) = 3(4y-9)

Expand the left side of the equation:
27x - 63 + 24x - 33 = 12y - 27

Combine like terms:
51x - 96 = 12y - 27

Rearrange the terms:
51x - 12y = 96 - 27
51x - 12y = 69

5(3-2y) - 4(9-y) = 3(y+5)

Expand the terms:
15 - 10y - 36 + 4y = 3y + 15

Combine like terms:
-6y - 21 = 3y + 15

Rearrange the terms:
-6y - 3y = 15 + 21
-9y = 36
y = -4

Therefore, the solution to the system of equations is x = 3, y = -4.