Répondre :
A=8/15-(2/5+1)
=8/15-(2/5-5/5)
=8/15-(-3/5)
=8/15+9/15
=17/15
B=7/20-(-2/15)-9/30
=21/60+8/60-18/60
=11/60
=8/15-(2/5-5/5)
=8/15-(-3/5)
=8/15+9/15
=17/15
B=7/20-(-2/15)-9/30
=21/60+8/60-18/60
=11/60