Tolong bantu saya mengerjakan No 12-13

A) 4(2x+6)+4(2x-2)+4(3x+4) = 228
8x+24+8x-8+12x+16 = 228
28x+32 = 228
28x = 196
X = 7 cm

B) (2x+6) x (2x-2) = (14+6) x (14-2) = 20 x 12 = 240 cm²

C) (2x+6) x (2x-2) x (3x+4) = (14+6) x (14-2) x (21+4) = 20 x 12 x 25 = 6000 cm²