Jawabanmu

2014-02-13T19:24:20+07:00
3x+12=7x-8
3x-7x=-8-12
-4x=-20
x=5

x+2
5+2
=7
2014-02-13T19:26:06+07:00
3x+12=7x-8
3x-7x=-12-8
-4x=-20
x= -20 : -4 
x = 5

x+2
5+2 = 7