[tex]bonjour\\\\\\f (x) = 3 x + 1 \\affine \\\\f ( 0) = 1 \\f ( -2) = - 6 + 1 = - 5 \\\\3 x + 1 = - 13 \\3 x = - 13 - 1\\3 x = - 14\\x = - 14/3 \\\\\\3 x + 1 = 7 \\3 x = 7 - 1 \\3 x = 6 \\x = 2 \\\\\\[/tex]
