(3x^2y - 2xy)³ ^ ( a - b)³ = a³ - 3a²b +3ab² - b³ in this case a = 3x^2y & b = 2xy so we have (3x^2y)³ - 3 (3x^2y)²2xy + 3(3x^2y)(2xy)² - (2xy)³ = 27x^6y - 3(9x^4y)2xy +(9x^2y)4x²y² - 8x³y³ 27x^6y - 54x^4yxy + 36x^2yx²y² - 8x³y³ I hope I got it right
