Begin with drawing a box with dimensions of x*x*h
Therefore the Volume of the box is V=768cm^2
Making 'h' the subject, h=768/x^2
Now to find the amount of tape used, let it be 'T'
T=8x+4x+4h (8x is the sum of the width and length and 4x+4h is the sum of the height and width)
Therefore...