This solution won't work if x is not an integer

let a =
let b =
a - b = 2
a³ - b³ = 56

assuming integral
(3,1) difference = 2 difference of cube not 56
(4,2) difference = 2 difference of cubes is 56
6x+28 = 4³
6x-28 = 2³
working simultaneously, x = 6

second possibility
(-2,-4) difference = 2 difference of cubes is 56
6x+28 = -8
6x-28 = -64
working simultaneously, x = -6

Solution set x (-6,6)

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