Usamos ( x + y )² = x² + 2 x y + y²
[tex](7a {)}^{2} + 2 \times 7a \times 11b + (11b {)}^{2} [/tex]
elevamos el factor a la potencia
[tex]49 {a}^{2} + 2 \times 7a \times 11b + (11b {)}^{2} [/tex]
calculamos
[tex]49 {a}^{2} + 154ab + (11b {)}^{2} [/tex]
elevamos el factor a la potencia
[tex]49 {a}^{2} + 154ab + 121 {b}^{2} [/tex]
