Bonjour
5/7 + (2/7 - 5)
= 5/7 + [2/7 - (5 x 7) / (1 x 7)]
= 5/7 + (2/7 - 35/7)
= 5/7 - 33/7
= 28/7
= (7 x 4) / (7 x 1)
= 4.
7/3 - 4/3 : 2/5
= 7/3 - 4/3 x 5/2
= 7/3 - 20/6
= (7 x 2) / (3x 2) - 20/6
= 14/6- 20/6
= - 6/6
= - 1
4/5x (5/4 + 1) - 3/10
= 4/5 x [5/4 + (1 x 4) / (1 x 4)] - 3/10
= 4/5 x (5/4 + 4/4) - 3/10
= 4/5 x 9/4 - 3/10
= 36/45 - 3/10
= (9 x 4) / (9 x 5) - 3/10
= 4/5 - 3/10
= (4 x 2) / (5 x 2) - 3/10
= 8/10 - 3/10
= 5/10
= (5x 1) / (5x 2)
= 1/2.
