(x^4+x^3-x-1) делим на x+1 и получим (x^3-1)
т.е. (x^3-1)(x+1)=0
x=-1, x^3=1, x=1, x=+-1
Х^2+4ху-5у^2=(х^2+2*х^2*2у+4у^2)-9у^2=(х+2у)^2-(3у)^2=(х+2у-3у)(х+2у+3у) =(х-у) (х+5у)
<span>16 cos20 cos40 cos60 cos80=8 cos20cos40cos80=8cos20cos40cos80sin20/sin20=4sin40cos40cos80/sin20=2sin80cos80/sin20= sin160/sim20=sin(180-20)/sin20=sin20/sin20=1
соs60=1/2</span>
https://tex.z-dn.net/?f=y_0%3D0%2C%200%3D-%20%5Cfrac%7B3%7D%7B4%7D%20x_0-12%3B%20x_0%3D12%3A%28-%5Cfrac%7B3%7D%7B4%7D%20%29%3D-16
Ответ:(-16;0)