1 ) ax = (3 - 5 x )² - ( 4 - 3 x )²
= (9 - 30 x +25x² ) - ( 16 -24 x + 9x² )
= 9 - 30 x + 25 x² -16 +24 x - 9 x²
= -7 - 6 x + 16 x²
2) a = 16 x² - 6 x - 7 = 2x (8x - 3) -7
3) a = 0
ax = (3 - 5x)² - (4 - 3x )²
a (0) = ( 9 - 0 - 0) - (16 - 0 - 0)
= 9 - 16
= 7
4) a (-1) = ( 9 + 30x +25 x²) - ( 16 + 24x - 9x²)
= 9 + 30 x + 25 x² - 16 - 24 x + 9x²
= -7 + 6x + 34 x²
5 ) (8x + 7) ( -2 x - 1) = 0
-16x² - 8x - 14 x - 7 = 0
-16 x² - 22 x - 7 = 0
- 16 x² -22 x - 7 = 0
on a donc a = -16 b = -22 et c = -7
