-0,7*10000-8*100-26=-7000-800-26=-7826
<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>
D=576-4*1*108=576-432=144
х1=(24+12)\2=18
х2=(24-12)\2=6
2) D=121-4*24*1=121-96=25
х1=(11-5)\2=3
х2=(11+5)\2=8
3)D=81-4*1*14=81-56=25
х1=-(9+5)\2=-2
х2=(-9-5)\2=-7
X^2+6x+4=0
D=6^2-4*2*4=36-32=4
х^1=-6-2/4=2
x^2=-6+2/4=1
Ответ:х^1=2;x^2=1
x^2+106x+693=0
<span> D=(106)²-4*693=11236-2772=8468, X1=(-106-92)/2=-99; X2=(-106+92)/2=-7.</span>