a)2x +49 = 9                 b 2x - 25 = 16/9

2x = 9 - 49                       2x = 25 + 16/9

2x = 40                            2x = 4,5

2x/2 = 40/2                     2x/2 = 4,5/2

x = 20                             x = 2,25 pas sure