\(\left(-x^2y\right)^3.\dfrac{1}{2}x^2y^3.\left(-2xy^2z\right)^3\\ =\left(-1\right)x^6y^3.\dfrac{1}{2}x^2y^3.\left(-8\right)x^3y^6z^3\\ =\left[\left(-1\right).\dfrac{1}{2}.\left(-8\right)\right]\left(x^6.x^2.x^3\right)\left(y^3.y^3.y^6\right).z^3\\ =4x^{11}y^{12}z^3\)