Réponse:
1)
[tex] = \frac{1}{4} \times ((1 + 5)^{2} - (1 - 5)^{2}) \\ = \frac{1}{4} \times (64 - 16) \\ = \frac{48}{4} = 12[/tex]
2)
[tex] = \frac{ 1}{4} \times (( - 2 + - 3)^{2} - ( - 2 - - 3)^{2}) \\ = \frac{1}{4} \times (25 - 1) \\ = \frac{24}{4} = 6[/tex]
3)
[tex] = \frac{1}{4} \times ((a + b)^{2} - (a - b)^{2}) \\ = \frac{1}{4} \times (( {a}^{2} + 2ab + {b}^{2}) - ({a}^{2} - 2ab + {b}^{2} ) \\ = \frac{1}{4} \times (4ab) \\ = ab[/tex]
