Bonsoir,
(5/ 7)/( 15/2 )
5/7 * 2/15
= 10/105 = 2/21
(5/3) / (7/9)
= 5/3* 9/7
= 45/21 = 15/7
(12/5) / (6/7 )
= 12/5 * 7/6
= 84/30 = 14/5
P= 18/4*8/6
= 144/24 = 24/4 12/2 = 6
R = 2,7/0,15 * 0,25/3
=0,675/ 0,45 = 1,5
S =12/18* 45/4
= 540/ 72 = 270/36 = 30/4 = 15/2