(1)4x=168
x=168/4
x=42
(2)x/3=5.5
x=3*5.5
x=16.5
(3)0.9x=2.44
x=2.43/0.9
x=2.7
(4)x/15=180
x=180*15
x=2700
(5)14x=7
x=7/14
x=0.5
(6)x/2.5=0.8
x=2.5*0.8
x=2