(3-х)(х^2+3х+9)-х(х+5)(х-5)=23

( 3 - x)(x^2 + 3x + 9 ) - x(x + 5)(x- 5) = 23
- ( x - 3)(x^2 + 3x + 9) - x(x - 5)(x +5) = 23
- ( x^3 - 27) + x( x^2 - 25) - 23 = 0
- x^3 + 27 + x^3 - 25x - 23 = 0
- 25x = - 4
25x = 4
x = 4/25
x = 0,16