Répondre :
a) 1/9-15/9 *1/6
=1/9-15/54
=6/54-15/54
=-9/54
=-3/18
=-1/6
b) 5/11-8/11*4/5
=5/11-32/55
=25/55-32/55
=-7/55
=1/9-15/54
=6/54-15/54
=-9/54
=-3/18
=-1/6
b) 5/11-8/11*4/5
=5/11-32/55
=25/55-32/55
=-7/55