I don't know why being in a single line is so important, especially since it makes it more confusing, but if you insist for some reason, you can use deal():
[A, D] = deal((B - C).^3, (E - F).^3)
It assigns (B - C).^3 to A, and (E - F).^3 to D. It does not sum them together, so you still need to do
K = (A + D)
