You can put this solution on YOUR website! x^(4/3)[x^(2/3) + 3x^(5/3) - 4x^(8/3)]
While multiplying we add the powers of the same bases.
= x^(4/3 + 2/3) + 3x^(4/3 + 5/3) - 4x^(4/3 + 8/3)
= x^(6/3) + 3x^(9/3) - 4x^(12/3)
= x^2 + 3x^3 - 4x^4
Good Luck!!!