[tex]a = 2x - 3(6x + 1) - (x - 5)(2x - 1) \\ = 2x - 18x - 3 - (2x {}^{2} - x - 10x + 5) \\ = - 16x - 3 - 2 {x}^{2} + x + 10x - 5 \\ = - 2x {}^{2} - 5x - 8[/tex]
A pour x = -1
[tex]a = 2 \times ( - 1) - 3 \times 6( - 1 + 1) - ( - 1 - 5) \times 2 \times ( - 1- 1) \\ = - 2 - 3 \times 6 \times 0 - ( - 6) \times 2 \times ( - 1) - 1 \\ = - 2 - 0 + 6 \times 2 \times ( - 1) - 1 \\ = - 2 - 12 - 1 \\ = - 15[/tex]
