<span>1)(cos36°+sin^2 18°)/cos18°=(сos²18-sin²18+sin²18)/cos18=cos²18/cos18=cos18
2)cos80°/(cos40°+sin40°)(cos²40-sin²40)/(cos40+sin40)=</span>
=(cos40-sin40)(cos40+sin40)/<span>(cos40+sin40)=cos40-sin40</span>
<span>Х²+2х+4=0
D=4-16<0 корней нет
</span>
<span>х² -5х+3=0
D=25-12=(√13)²
х₁=(5+</span><span>√13)/2
х₂=(5-</span><span>√13)/2</span>
Х^3-2х^2у-4ху^2+8у^3=(х-2у)^2(х+2у)
4=к*0+м
м=4
-16=2к+4
2к=-20
к=-10
ответ:к=-10, м=4