Question 297161
 –x + 3y = 6
  x – 9y = 9 add.
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-6y=15
y=15/-6
y=-2.5 ans.
-x+3*-2.5=6
-x-7.5=6
-x=6+7.5
-x=13.5
x=13.5/-1
x=-13.5 ans.
Proof:
-13.5-9*-2.5=9
-13.5+22.5=9
9=9