Jawabanmu

2014-08-20T17:00:20+07:00
X+2y=84
2x+y=84
________
2x+4y= 168
2x+y. = 84
------------- --
0. + 3y= 84
Y= 28

2x+ 28=84
2x. =56
X. = 28

X+y=. 28+28 =56
2014-08-20T17:11:39+07:00
maaf tadi ada salah perhitungan..

x+2y = 84 | 2 | 2x+4y = 168
2x+y = 84 | 1 | 2x+y = 84
                           3y = 84
                             y = 28

x+2y = 84
x+2(28) = 84
x+56 = 84
x = 84-56
x = 28

x+y = 28+28 = 56