Question

B=a^3-b^3-3ab biết a-b = 1

Answer 1

Ta có: B = a³ - b³ - 3ab

= (a - b)(a² + ab + b²) - 3ab

= a² + ab + b² - 3ab

= a² - 2ab + b²

= (a - b)² = 1² = 1

Answer 2

\(B=a^3-b^3-3ab=\left(a-b\right)\left(a^2+ab+b^2\right)-3ab=a^2+ab+b^2-3ab=a^2-2ab+b^2=\left(a-b\right)^2=1\)