Bonjour
a)
7y/4 +6 = 24/5 - 21y
32y/20 + 30/5 = 96/5 - 105y/5
32y +105y = 96 -30
137y = 66
y = 66/137
b)
3a/4 +3a = 6 +14a/4
3a/4 + 12a/4 = 24/4 +14a/4
3a+12a -24a -14a = 24
-23 a = 24
a = -24/23
c)
21b/2 +3/5 = 6/5 - 28b
105b/10 +6/10 = 12/10 - 280b/10
105b +280b = 12 -6
385b= 6
b = 3/385
d)
15x/7 +21/2 = (3x -9)/2
30x/14 + 147/14 = 21x/7 -63/7
30x -21x = -63 -147
9x = 210
x = 210/9 ou 70/3
