9/14 - x = 5/4
Numitor comun
14=2•7
4=2^2
________
cmmmc=2^2 • 7 = 28
(9•2)/28 - 28x/28 = (5•7)/28
18-28x=35
-28x=35-18
-28x=17
x=(-17/28)
