X^3 + 2x^2 - 36x - 72 = 0
x^2 (x + 2) - 36(x + 2) = 0
(x^2 - 36)(x + 2) = 0
x + 2 = 0
x = - 2 ;
x^2 = 36
x = ± √36
x = ± 6
Ответ
- 6; - 2; 6
Х
5+х
х(5+х)=66
х²+5х-66=0
Д=5²-4*(-66)=25+264=289=17²
х=(-5±17)/2
х1=-22/2=-11<0
х2=12/2=6
х=6
х+5=11
ответ 6 и 11
cos^2 75° - sin^2 75° = cos 150 = - √3/2