Упростите выражение (а+1)^3–(а–1)^3

(а+1)^3–(а–1)^3=(a+1-a+1)(a²+2a+1+a²-1+a²-2a+1)=2(3a²+1)

(a +1)³ - (a - 1)³ = (a + 1 - a + 1)((a +1)² - (a+1)(a -1 ) + (a - 1)²) = 2(a² +2a +1 -a² +1 +a² - 2a +1) = 2(a² +4a + 3) = 2(a +1)(a + 3)