The volume of the region between the first octant and the plane 3x+6y+4z =12

The correct answer is 4, what is the process to get that answer?

Graph:

O eq1 : 3 x + 6 y + 4z = 12 : + Input... 6 4 2 - - -1 - -6 -4 2. O 6 -2 GeoGebra 3D Calculator15.) Bounded by the First octant and 3 x+ 64 + 48 = 12 4 (2- 3X 7 27 dr dy dx 42= 12- 3x - 64 o o 2 = 3 - 3X- 6y 4 WN X int 0= 3-3x - 0 9 3x = 3 2 y 3x= 12 9 Y X = 4 0= 12-3x -69 y int = 2 by = 12-3X 2 int = 3 y= 2-3X 6