Bonjour pouvez vous m'aider a me corriger merci

Nommer ces molecules:
             CH3
                '
CH3-CH-CH2-CH-CH3
                                      '  
                                    CH3
la molecule est 2,4-dimethylpentane


CH3-CH-CH2
               '            '
             CH3     CH3
La molecule est 2,3-dimethylpropane


CH3-CH-CH2-CH-CH3
                '                 '
              CH2         CH3
                  '
               CH3
le nom est 5-Methylhexane

                                                 CH3
CH3-CH2                            '
                         -CH-CH2-C-CH2-CH3
             CH3                           '
                                                 CH3
JE n'ai pas trouvé