bonjour
[tex]3 x + 5 = 5 x + 7\\\\3 x - 5 x = 7 - 5 \\- 2 x = 2\\x = - 1 \\\\7 x + 9 = 2 x - 1\\7 x - 2 x = - 1 - 9 \\5 x = - 10\\x = - 2 \\\\\\2 - 3 x = 4 x - 3 \\- 3 x - 4 x = - 3 + 3 \\- 7 x = 0 \\x = 0 \\\\\\7 x + 5 x - 3 = 3 x + 1 \\12 x - 3 x = 1 + 3 \\9 x = 4 \\x = 4/9 \\\\\\4 x - 5 = 3 x - 2 x + 7 \\4 x - 3 x + 2 x = 7 + 5 \\3 x = 12 \\x = 4 \\\\[/tex]
