Semplifica le seguenti espressioni.
(2x−x2+3)−(x2−4x−5)+(−2x2+3x−4)(2x-x^2+3)-(x^2-4x-5)+(-2x^2+3x-4)(2x−x2+3)−(x2−4x−5)+(−2x2+3x−4)
2x−x2+3−x2+4x+5−2x2+3x−42x-x^2+3-x^2+4x+5-2x^2+3x-42x−x2+3−x2+4x+5−2x2+3x−4 === (−x2−x2−2x2)+(2x+4x+3x)+(3+5−4)(-x^2-x^2-2x^2)+(2x+4x+3x)+(3+5-4)(−x2−x2−2x2)+(2x+4x+3x)+(3+5−4) === −4x2+9x+4-4x^2+9x+4−4x2+9x+4