Bonsoir,
1.
(8x+1)(5-2x)>(7-8x)(5-2x)
40x - 16x^2 + 5 - 2x > 35 - 14x - 40x + 16x^2
16x^2 - 16x^2 + 40x + 40x - 2x + 14x > 35 - 5
12x > 30
x > 30 / 12
x > 5 / 2
2.
x^2 + 3x - 12 < x^2 + 5x -13
X^2 - x^2 + 3x -5x < -13 + 12
-2x < -1
2x > 1
x > 1 / 2
Bonne soirée