(x+1)(x⁷-x⁶+x⁵-x⁴+x³-x²+x-1) = x⁸+x⁷-x⁷-x⁶+x⁶+x⁵-x⁵-x⁴+x⁴+x³-x³-x²+x²+x-x-1 = x⁸-1
3^7 * 3^5 = 3^12 = 531441
4^9 : 4^6= 4^3 = 64
(2^2)^3= 2^6 = 64
3^5 * 3^7 = 3^12= 531441
(а^3)^4 * а^2 = а^14
X^3*y^3-c^3=(xy)^3-c^3=(xy-c)*((xy)^2+ xyc+c^2)
Решаем как квадрaтное ( arctgx = z)
D = 25- 16 = 9
arctgx = (5+3)/4 = 2 arctgx = (5-3)/4 = 1/2
-π/2 < arctg x < π/2, ⇒ arctg x = 1/2