Question

Desenvolva (a-1) ao cubo

Answer 1

(x-y)³ = x³ - 3.x².y + 3.x.y² - y³

(a-1)³ = a³ - 3.a².1 + 3.a.1² - 1³

(a-1)³ = a³ - 3a² + 3a - 1 ✓

Answer 2

(a − 1)³ =  

(a − 1)(a − 1)² =

(a − 1)(a² − 2a + 1) =

a³ − 2a² + a − a² + 2a − 1  =

Logo,

(a−1)³ = a³ − 3a² + 3a − 1.