(х-3)(х2+3х+9)-х(х+5)(Х-5)=23

(х - 3)(х^2 + 3х + 9) - х(х + 5)(Х - 5) = 23;x * x^2 + x * 3x + x * 9 + (-3) * x^2 + (-3) * 3x + (-3) * 9 - x(x^2 - 5^2) = 23;x^3 + 3x^2 + 9x - 3x^2 - 9x - 27 - x(x^2 - 25) = 23;x^3 + 3x^2 + 9x - 3x^2 -9 x - 27 - x^3 + 25x = 23;25x = 23 + 27;25x = 50;x = 50 : 25;x = 2.Ответ. 2.