Résoudre les equation suivante ( svp je comprend rien) 5x=2 7x+3=5 12-5x=4 21x-5=3x+2 -7x+15=3-2x 5(2x-6)=3(3-2x)

5x = 2
x = 2 / 5
x = 0,4

7x + 3 = 5
7x = 5 - 3
7x = 2
x = 2 / 7 

12 - 5x = 4
- 5x = 4 - 12
- 5x = - 8 
x = [tex] \frac{- 8}{- 5} [/tex]
x = 1,6

21x - 5 = 3x + 2
21x - 3x = 2 + 5
18x = 7
x = 7 / 18

- 7x + 15 = 3 - 2x
- 7x + 2x = 3 - 15
- 5x = - 12
x = [tex] \frac{- 12}{- 5} [/tex]
x = 2,4

5 (2x - 6) = 3 (3 - 2x)
10x - 30 = 9 - 6x
10x + 6x = 9 + 30
16x = 39
x = 39 / 16

*5x=2
x=2/5

*7x+3=5
7x=5-3
7x=2
x=2/7

*12-5x=4
-5x=4-12
-5x=-8
x=-8/-5
x=8/5

*21x-5=3x+2
21x-3x=2+5
18x=7
x=7/18

* -7x+15=3-2x
-7x+2x=3-15
-5x=-12
x=-12/-5
x=12/5

* 5(2x-6)=3(3-2x)
10x-30=9-6x
10x+6x=9+30
16x=39
x=39/16