Arrive pour ses deux exos

18.)

a.)
 3x/4 = 6/5
3x * 5 = 6 * 4
15x = 24
x = 24/15
x = 8/5

b.)
7/5x = 2/5
x = 2/5 * 7/5
x = 2/7

c) 
5x/2 = 3/4
5x * 4 = 3 * 2
20x = 6
x = 6/20
x = 3/10


19.)

a.)
11x/3 = 22/9
11x * 9 = 22*3
99x = 66
x = 66/99
x = 2/3

b.)
4/13x = 6/26
x = 6/26 * 13/4
x = 3/26

c.)
9x/2 = 3/6
9x * 6 = 3 * 2
54x = 6
x = 6 / 54
x = 1 / 9