Réponse :
Bjr,
On a :
1)
7-3(x+5) = 7(2-2x)
7-3x-15 = 14 - 14x (distributivité)
-3x + 14x = 14-7+15
11x = 22
x = 22/11
x = 2
2)
1- 2x/5 = 3 + x/4
1*20-2x/5 * 20 = 3*20 + x/4 * 20
20-8x = 60 + 5x
-8x - 5x = 60-20
-13x = 40
x = -40/13
3)
3 - 4x/5 = 2x + 1
-4x/5 = 2x-2
-4x-10x = -2*5
-14x = -10
x = 10/14
x = 5/7
J'espère avoir pu vous aider
bonjour
[tex]7 + 3 x - 15 = 14 - 14 x \\3 x + 14 x = 14 - 7 + 15\\17 x = 22\\x = 22/17 \\\\\\1 - 2 x /5 = 3 + x / 4\\20/20 - 8 x /20 = 60/20 + 5 x /20 \\- 8 x - 5 x = 60 - 20\\- 13 x = 40 \\x = - 40/13 \\\\\\3 - 4 x / 5 = 2 x + 1 \\15/5 - 4 x / 5 = 10 x/5 + 5/5\\- 4 x - 10 x = 5 - 15 \\- 14 x = - 10 \\x = 10/14 = 5/7 \\\\\\[/tex]
