( 2x - 7 ) ( -6x + 5 ) - 4( 1 - 8x - 3x²)
= (-12x² + 10x + 42x - 35 ) -4 + 32x + 12x²
= -12x² + 12x² + 10x + 42x + 32x -35 - 4
= 84x - 39
2) pour x = 1
84*1 - 39
= 84 - 39
= 45
