Odpowiedzi

2009-10-04T14:31:19+02:00
(2x-3y)³=8x³-36x²y+54xy²-27y³
(2x+3y)³=8x³+36x²y+54xy²+27y³
(2x-3y)³-(2x+3y)³ =8x³-36x²y+54xy²-27y³-(8x³+36x²y+54xy²+27y³)=
=8x³-36x²y+54xy²-27y³-8x³-36x²y-54xy²-27y³
=-72x²y-54y³