Semplifica le seguenti espressioni.
(a+3b−c)−(a−2b−c)−(a−4b)(a+3b-c)-(a-2b-c)-(a-4b)(a+3b−c)−(a−2b−c)−(a−4b)
a+3b−c−a+2b+c−a+4ba+3b-c-a+2b+c-a+4ba+3b−c−a+2b+c−a+4b === (a−a−a)+(3b+2b+4b)+(−c+c)(a-a-a)+(3b+2b+4b)+(-c+c)(a−a−a)+(3b+2b+4b)+(−c+c) === −a+9b-a+9b−a+9b === 9b−a9b-a9b−a