Bonjour,

(x-5)²=(x+3)(x-3)

x² - 10x + 25 = x² - 3²

x² - x² + 25 + 9 = 10x

10x = 34

x = 34/10

x = 17/5

7(-2x+4)> 4x

-14x + 28 > 4x

28 > 4x + 14x

18x < 28

x < 28/18

x < 14/9

x € ] -inf ; 14/9 [

(x+7)≤ -4x+9

x + 4x ≤ 9 - 7

5x ≤ 2

x ≤ 2/5

x € ] -inf ; 2/5 ]