Given ((a + b(√(cx))))^(1/3) + ((a − b(√(cx))))^(1/3) = d
Determine x in terms of a, b, c and d.
Solution:
Let A = ((a + b(√(cx))))^(1/3) and B = ((a − b(√(cx))))^(1/3)
⇒ A^3 = a + b(√(cx)) and B^3 = a − b(√(cx))
⇒ A^3 + B^3 = 2a
⇒ (A + B)[(A + B)^2 − 3AB)] = 2a
⇒ d(d^2 − 3AB) = 2a
⇒ AB = ((d^3 − 2a)/(3d))
((a + b(√(cx))))^(1/3) × ((a − b(√(cx))))^(1/3) = ((d^3 − 2a)/(3d))
a^2 − b^2 cx = (((d^3 − 2a)^3 )/(27d^3 ))
x = (a^2 /(b^2 c)) − (((d^3 − 2a)^3 )/(27b^2 cd^3 ))

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