(1)(-1)^3*(3a^3b^2)^3*(-2/3a^2b^3)^3
=-1*27a^9b^6*(-8/27a^6b^9)
=8a^15b^15
(2)[-2(x-y)^2]^2*(y-x)^3
=4(x-y)^4*[-(x-y)^3]
= -4(x-y)^7
(3)2(x-2)(x+4)
=2(x²+2x-8)
=2x²+4x-16
(4)(3x+4y)(2x-3y)
=6x²-xy-12y²