Sagot :
a ) -1x 4/ 15x4 + 1x3 / 20x3
-4/60 + 3/60
-1/60
b ) 3x5 / 7x5 + (-1x7 / 5x7 )
15 / 35 - 7 / 35
8/35
c ) -5x5 / 12x5 + 4x4 / 15x4
-25 / 60 + 16 / 60
-9 / 60
-3 / 30
-4/60 + 3/60
-1/60
b ) 3x5 / 7x5 + (-1x7 / 5x7 )
15 / 35 - 7 / 35
8/35
c ) -5x5 / 12x5 + 4x4 / 15x4
-25 / 60 + 16 / 60
-9 / 60
-3 / 30