je dois effectuer -6/5×15/7 et 2/3:-4/3

Bonsoir , 
-6/5 × 15/7
= -90/35
= -18/7
2/3 ÷ -4/3
= 2/3 × 3/-4
= 6/-12
= 1/-2

-6/5*15/7=-6/5*3×5/7=-6×3/7=-18/7
2/3÷-4/3=2/3×-3/4=-2/4=-1/2 ok