(-2a^2b)(2/3ab^3)(-6b^2c^3)
=8a³b的6次方c³
(x+y)(x-y)-(x-2y)(x+2y)
=x²-y²-x²+4y²
=3y²
(3x-2y)^2-(3x-y)(3x+y)
=9x²-12xy+4y²-9x²+y²
=5y²-12xy
(x+1)(x-1)(x^2-1)-(x^2+1)^2
=(x²-1)(x²-1)-(x²+1)²
=x^4-2x²+1-x^4-2x²-1
=-4x²
如果本题有什么不明白可以追问,