[tex]1)c = (6x - 7) {}^{2} - (2x - 3) {}^{2} \\ = {36x}^{2} - 49 - ( {4x}^{2} - 9) \\ = {36x}^{2} - 49 - {4x}^{2} + 9 \\ = {32x}^{2} - 40[/tex]
[tex]2)c = {32x}^{2} - 40 \\ = 8( {4x}^{2} - 5)[/tex]
3) On a (4x-4)=1/(8x-10)
donc (4x-4)(8x-10)=0
