(2+x)³ = x³ + 6x² + 12x + 8
(a-2)³ = a³ - 6a² +12a - 8
(5-b)³ = -b³ +15b² -75b+125
(y+3)³ = y³ +9y²+27y+27
2x²+8x-111-6x²-18x+10x+30<0
-4x²-81<0
4x²+81>0
x∈(-∞;∞)
Cos(4π+t)=cost=12/13
sint=-√(1-cos²t)=-√(1-144/169)=-√25/169=-5/13
(6|cost|-|sint|)/cost=(72/13-5/13):12/13=67/13*13/12=67/12=5 7/12