Answers

2014-11-12T20:45:48+08:00
2x + y = 1    ----equation 1
-x + y = -5   ----equation 2
subtract equation 2 from equation 1
    2x + y = 1
-   -x  + y = -5
    3x  = 6
      x = 2
substitute x=2 to equation 2
-x + y = -5
-2 + y = -5
y = -5 + 2
y = -3
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