The First one (A) because it’s a straight line
X2 + 12 = 7x x2 – 7x + 12 = 0factor the equation (x – 3 ) ( x – 4 ) = 0 Then equating both factor to 0 X – 3 = 0 X = 3 And X – 4 = 0 X = 4 So the answer is X = 3 X =4
So each dimention is 32 by 8 by 10
so the surface area=2 times(8 times 10)+(2 times (32 times 10))+(2 times (8 times 32))=2 times 80+2 times 320+2 times 256=1312
if halved
just divide each by 2
(2 times 4 times 5)+(2 times 16 times 5)+(2 times 4 times 16)=(2 times 20)+(2 times 80)+(2 times 64)=40+160+128=328
the new surface area is 328 mm^2