Bonsoir,
a=(3/2+3/5)x(5/4 - 4/3)
(15/10 + 6/10 ) ( 15/12 - 16/12)
21/10 * -1/12 = -21/ 120 = -7/40
b=5-5x(-2x3+2x(-3))
5-5x(-6 -6x)
5-+30x +30x²
c=3/2+3/5x5/4 - 4/3
3/2 + 15/20 -4/3
3/2 + 3/4 -4/3
18/12 + 9/12- 16/12 = 11/12
d=5,5x100+230/10 - 57x4
550 + 23 - 228
345