<span>х(х+y)²-y(x-y)²+2y(x²+y²)</span>=x(x²+2xy+y²)-y(x²-2xy+y²)+2x²y+2y³=
=x³+2x²y+xy²-x²y+2xy²-y³+2x²y+2y³=x³+3x²y+3xy²+y³=(x+y)³
(x+y)³ при <span>х=2,5 , у=0,5
(2,5+0,5)³=3³=27</span>
<span>=1/хв минус 5=х в пятой</span>
2,56(а)
у=2х-4
2х^2-3х(2х-4)+4х^2+16-8х=12;
4х=-4
х=-1
ответ:-1