12 3 8 x 4 July 8, 2019 16 32 64 128 12 (- 3 x 2 8 2 x (- 4 3 x 12 )= 8 4x 12 x 2 )-( 4x 3 )= 8 x 3 12 8 4 2 3 x 1 24 3 1 3 8 12 x 1 4 5 5 12 3 8 x 4 9 3 12 5 8 x 4 12 x 8 )=- 3 x 47 12 3 8 x 9 1 4 12 7x 21 =- 8 3 x )+ 4x 12 8 x 3 ) 44 12 8x 3 x 4 3 8 x 4 x 12 drywall 12 3 4 x 8 1 2 12 3 x 4 9 8 2