Sagot :
Bonsoir
A + B
= 5/3 +10/21
= 35/21 +10/21 = 45/21 = 15/7
A - B
= 5/3 - 10/21 = 35/21 - 10/21 = 25/21
A x B
=5/3 x 10/21 = 50/63
A = 3/8 x (4/9 +2/3)
A = 3/8 x (4/9 +6/9)
A = 3/8 x 10/9
A = 30/72 = 15/36
B = 7/5 x 3/10 +1/5
B = 21/50 + 1/5
B = 21/50 + 10/50
B = 31/50
exo 1
A+B =5/3 +10/21
= 15/17*
A-B = 5/3 + 10/21
A-B = 25/21
si j'ai bien compris ;)
exo2
A= 3/8 x (4/9+2/3)
A= 3/8 x 10/9
A= 5/12
B= 7/5 x 3/10 + 1/5
B= 21/50 + 1/5
B= 31/50
voila ;)