Bonjour,
A=
(3/6 - 2/6) *3/2 +1
= 1/6 * 3/2 +1
= 3/12 + 12/12
= 15/12 = 5/4
B=
(3/5)² = 9/25
9/25 * 20/9 = 20/25 = 4/5
C=
1/3 -1/6 = 2/6 -1/6 = 1/6
4-3/4 *1/6
= 4 - 3/24
= 96/24 -3/24
= 93/24 = 31/8
D=
3/4 -4 = 3/4 - 16/4 = - 13/4
3/4 + 1/3 = 9/12 + 4/12 = 13/12
( -13/4) / ( 13/12)
= -13/4 * 12/13
= -4/12 = - 1/3