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Please help with AS-level Math

(a)Figure 2 shows a solid cuboid which is 3.5𝑥 cm wide, 4𝑥 cm long and h cm tall. The total surface area is 6804 cm^2.
Find an expression for h in terms of 𝑥.
b) Show that the volume of the cuboid, 𝑉, is given by
𝑉 􏰄=(95256x-392x^3)/15

Reply 1

TypicalNerd

Original post by chitaolee23

The surface area of a cuboid = 2(width)(height) + 2(length)(height) + 2(width)(length)

Can you sub in the given information, simply the expression and rearrange it to make h the subject?

Next, use the fact that volume = length x width x height and replace the h with the expression you found in the previous part.