Bonjour,

5x - 8 = -10

5x = -10 + 8 = -2

x = -2/5

-6x + 3 = 3x + 15

-6x - 3x = 15 - 3

-9x = 12

x = -12/9 = -4/3

4x - 7 = 2x + 13

4x - 2x = 13 + 7

2x = 20

x = 20/2 = 10

-7x + 8 = -4x + 12

-7x + 4x = 12 - 8

-3x = 4

x = -4/3

(3x - 6)(2x + 8) = 0

<=> 3x - 6 = 0

3x = 0 + 6 = 6

x = 6/3 = 2

<=> 2x + 8 = 0

2x = 0 - 8 = (-8)

x = -8/2 = (-4)

(5x - 10)(3x + 15) = 0

<=> 5x - 10 = 0

5x = 0 + 10 = 10

x = 10/5 = 2

<=> 3x + 15 = 0

3x = 0 - 15 = (-15)

x = -15/3 = (-5)