5 or -19
說明:
|x-2| : |x-9|= 3: 4
當x>9時,(x-2): (x-9)= 3: 4
3x-27=4x-8
x=-19
當x<2時,(2-x): (9-x)= 3: 4
27-3x=8-4x
當2<x<9時,(x-2): (9-x)= 3: 4
27-3x=4x-8
7x=35,
x=5