这题属于计算题.
3x(x-1)-5x(x+2)
=3x²-3x-5x²-10x
=-2x²-13x
(-1/6x²y)*xy²*(-3xyz)
=1/2x^4y^4z
(3x+2)(2x-3)
=6x²-9x+4x-6
=6x²-5x-6