X³=64/27 Cube root the answer ³√x³=³√64/27 x=4/3. Check: x=4/3 x³=(4/3)³ x³=64/27. As a result, the correct answer is 4/3 or 4 over 3. If you wonder why don't I choose the answer as ±4 over 3 because of this ±4/3 Choose positive first (4/3)²=64/27 Correct. However, then choose negative signs (-4/3)³=-64/27 Incorrect. Hope it help!