Question

(2a-1) (4a²+2a+1) при a=-1/2

Answer 1

разность кубов

x³ - y³ = (x - y)(x² + xy + y²)

x= 2a

y = 1

(2a-1) (4a²+2a+1) = (2a)³ - 1³ = 8a³ - 1

при a=-1/2

(2*-1/2)³ - 1 = (-1)³ - 1 = -2