Răspuns:
[tex](b - 2 {b}^{2} + 1)(1 - b) = b \times 1 - b \times b - 2 {b}^{2} \times 1 - 2 {b}^{2} \times ( - b) + 1 \times 1 + 1 \times ( - b) = {b}^{2} - 2 {b}^{2} + 2 {b}^{3} + 1 - b = - {b}^{2} + 2 {b}^{3} + 1 - b = 2 {b}^{3} - {b}^{2} - b + 1[/tex]
[tex](a - b)( {a}^{2} + ab + {b}^{2} ) = a \times {a}^{2} + a \times ab + a \times {b}^{2} - b \times {a}^{2} - b \times ab - b \times {b}^{2} = {a}^{3} + {a}^{2} b + a { b}^{2} - {a}^{2} b - a {b}^{2} - {b}^{3} = {a}^{3} - {b}^{3} [/tex]
