-15y + 21 = 12y + 204 + 60-15y + 21 = 12y + 264-15y - 12y = 264 - 21-27y = 243y = -9
Therefore, the solution is y = -9.
-15y + 21 = 12y + 204 + 60
-15y + 21 = 12y + 264
-15y - 12y = 264 - 21
-27y = 243
y = -9
Therefore, the solution is y = -9.