Jawabanmu

2013-12-05T19:30:50+07:00
Diket : x - y = 8
           2x^2 + xy - 3y^2 = 64
           2x + 3y = ... ?
perhatikan yah, (x-y)(2x+ 3y) = 2x^2 + xy - 3y^2
                        (8)(2x + 3y) = 64
                            2x + 3y = 64/8 = 8 ^-^
1 5 1
2013-12-05T23:06:25+07:00
X = 8 + y
2(8 + y )2 + (8+y) y - 3y2 = 64
y = - 8/5

x = 8 - 8/5
  = 32/5

2(32/5) - 3 (8/5) = 8