Jawabanmu

2014-04-26T22:09:15+07:00
X+5 = 3x-7
3x-x = 5+7
2x = 12
x = 6

BC = 2x-4
BC = 2*6-4
BC = 12-4
BC = 8
2014-04-26T22:48:25+07:00
Ab=dc
x+5=3x-7
7+5=2x
x=6

jadi bc adalah 2x-4>> 2(6)-4=12-4=8