c=5/3-2/3:5/6
d=-13/7+3/7:5/3
= 5/3 - 2/3 * 6/5
= 5/3 - 12/15
= 25/15 - 12/15
= 13/15
= -13/7 + 3/7 * 3/5
= -13/7 + 9/35
= -65/35 + 9/35
= -56/35
= -(7*8)/(7*5)
= -8/5
en espérant t'avoir aidé.
